GHK is a tiny 3-piece fragment of protein (glycine-histidine-lysine) that occurs naturally in human blood, saliva, and urine. It grabs onto copper very tightly, forming what's called GHK-Cu. Blood levels are highest around age 20 (roughly 200 ng/mL) and fall by more than half by age 60 (roughly 80 ng/mL), which is part of why it's marketed as an "anti-aging" ingredient. For decades it's been used in topical skincare and wound-care products. More recently, scientists have started testing it in animals for lung damage, gut inflammation, joint injuries, and age-related memory loss, but this newer research is almost entirely preclinical.
How strong is the evidence?
Of the 40 papers reviewed, most are lab (cell-culture) work, chemistry/sensor studies about copper detection, or animal experiments in mice, rats, and zebrafish. Only one paper measured GHK-Cu-related biology directly in people as part of an actual clinical comparison: a study linking naturally lower blood GHK levels to weaker chest muscles in COPD patients. The decades-old claims about topical anti-aging benefits in humans (tighter skin, fewer wrinkles) trace back mainly to review articles by one long-time GHK researcher, not to primary human trial data included in this literature set. Two 2026 physician-focused reviews state directly that there is no clinical trial data supporting GHK-Cu for joint, tendon, or muscle injuries, and that human dosing has never been established. Overall: a well-documented, biologically active molecule with a long safety history in skin products, but thin, mostly indirect human proof for anything beyond that.
Uses
What people use it for
Anti-aging and wrinkle-reducing skincare
Animal / labThis is by far the most common real-world use. GHK-Cu and related derivatives are widely sold in creams and serums for firmer, smoother-looking skin. The supporting science here is mostly lab experiments on skin cells and donated human skin samples, not full clinical wrinkle trials.
Wound and scar healing
Animal / labGHK-Cu is built into wound dressings and gels being tested for burns, infected wounds, and radiation-damaged skin. So far this work has been done in mice and lab models, not in people with real wounds.
Hair growth support
Animal / labGHK-Cu is marketed as a gentler alternative to minoxidil or finasteride for thinning hair. The research behind this is a topical-delivery study in mice, not a human hair-regrowth trial.
Joint, tendon, and muscle injury recovery (injectable use)
AnecdotalSome people use injectable GHK-Cu, often alongside peptides like BPC-157, hoping it speeds up recovery from injuries. Two 2026 orthopedic and sports-medicine reviews say plainly that no human clinical data exist for this use, and the only controlled injury study is in rats.
Potential benefits
What it may help with
Boosts collagen-building activity in skin cells and skin tissue samples
Animal / labIn human skin cells and donated human skin tissue tested in the lab, GHK-Cu increased several types of collagen and reduced the breakdown of elastin (the protein that keeps skin springy). Paired with hyaluronic acid, it more than doubled collagen IV production in real skin tissue samples. This is real biology, but it's lab testing on tissue, not a clinical trial tracking wrinkles on living people over time.
Calms inflammation and oxidative stress across many damaged-tissue models
Animal / labIn animal and lab studies, GHK-Cu repeatedly reduced inflammation and cell-damaging molecules called free radicals. This showed up in mouse lungs damaged by cigarette smoke, silica dust, or infection-triggering bacteria, in mice with colitis-like gut damage, and in zebrafish exposed to inflammatory triggers.
Linked to muscle protection in COPD, with muscle recovery shown in mice
Some human dataPeople with COPD had lower blood levels of natural GHK, and the lower the level, the weaker their chest muscles and the higher their inflammation markers - a real finding in real patients. When researchers then gave GHK-Cu to mice with smoke-damaged muscle, it restored muscle weight, muscle fiber size, and grip strength.
Studies:36905132Speeds up wound healing in animal models
Animal / labIn mice, dressings and liposome formulations containing GHK-Cu helped burns and infected wounds heal faster by boosting new blood vessel growth and cell turnover, cutting healing time to about 14 days in one burn study.
Improved memory and lowered brain inflammation markers in aging mice
Animal / labOld mice given a nose-spray version of GHK-Cu daily for two months did better on memory and navigation tests, and showed fewer signs of brain inflammation and nerve damage than mice given a placebo spray. This hasn't been tested in aging humans yet.
Temporarily helped joint healing after ligament surgery in rats
Animal / labInjected into the knee after ACL (ligament) surgery in rats, GHK-Cu improved joint stability and graft strength at 6 weeks. But the benefit faded by 12 weeks once the injections stopped, and orthopedic reviews confirm there is still no human data for joint or tendon injuries.
What to watch for
Side effects & risks
- Mild
Topical use appears well tolerated
In a study using microneedles to help GHK-Cu penetrate skin, researchers saw no signs of skin irritation. Topical GHK-Cu products have a long track record in cosmetics without major reported skin reactions in the literature reviewed.
- Moderate
Safety at injectable or systemic doses is simply unknown in humans
No human trial in this literature set tested GHK-Cu given by injection or taken systemically. Two 2026 medical reviews specifically flag that rigorous human safety data for GHK-Cu (and similar unapproved peptides) is scarce, so anyone using it that way is working without safety proof.
- Mild
Theoretical concern for people who already have too much copper in their body
GHK-Cu works by delivering copper into tissue. There's no study in this literature showing it causes copper overload, and one study even found GHK protected against copper-related heart toxicity in zebrafish. Still, because it's fundamentally a copper-delivery molecule, people with a copper-metabolism disorder should be cautious as a matter of basic logic, not because a study found harm.
Dosing
Dosing — what studies used
There is no established, tested human dose for GHK-Cu, for any use. Two 2026 medical reviews say directly that dosing, frequency, and duration for human use "remain unknown." Nearly everything we know about dosing comes from animal studies (mostly mice and rats) using injected or intranasal GHK-Cu, plus lab formulation studies figuring out how to get it through skin for cosmetic products. Commercial creams and serums list GHK-Cu as an ingredient, but the concentrations manufacturers use are their own choice - they aren't based on the clinical dosing research reviewed here. Treat any number below as "what a study tested," never as a recommended dose for a person.
Knee ligament (ACL) healing after surgery - rat study
Animal study0.3 mg/mL or 3 mg/mL GHK-Cu solution injected into the joint
Once a week · 4 weeks, starting 2 weeks after surgery · Intra-articular injection
Improved joint stability and graft stiffness at 6 weeks, but the effect faded by 12 weeks once injections stopped. Rat data only - never tested in human joints.
Lung inflammation and fibrosis models (mice)
Animal study0.2, 2, or 20 micrograms per gram of body weight per day
Every other day · About 3 weeks (fibrosis model) up to 12 weeks (emphysema model) · Intraperitoneal injection
Higher doses generally produced stronger anti-inflammatory and antioxidant effects in mice. No human-equivalent dose has been established.
Smoke-induced muscle loss (mice, modeling COPD)
Animal study0.2 or 2 mg/kg body weight
Repeated dosing during the smoke-exposure period (exact schedule not detailed in the abstract) · Duration of the smoke-exposure protocol · Injection (exact route not fully specified)
The higher dose produced the largest improvements in muscle mass and grip strength in smoke-exposed mice.
Brain aging and cognitive decline (mice)
Animal study15 mg/kg
Once daily · 2 months · Intranasal (nose-spray/atomizer device)
Improved memory-task performance and lowered brain inflammation markers in aged mice. Researchers noted this delivery method could plausibly be tested in humans next, but it hasn't been yet.
GHK-Cu is not an approved prescription drug, so there's no official drug-label dosing. It's sold mainly as a cosmetic ingredient, where concentration and quality aren't standardized by the research reviewed here. Anyone considering injectable or high-dose use should understand they are working entirely outside of tested human dosing.
These figures describe what researchers used in studies. They are not a recommendation or a prescription.
Mechanism
How it works
GHK is a natural fragment your body already makes and carries in your blood, and it has an unusually strong grip on copper, which is why it's almost always studied as the GHK-Cu pair. Copper is needed by several enzymes that build and repair tissue, including ones that make collagen and elastin (the proteins that keep skin firm) and ones that help build new blood vessels. In lab and animal studies, GHK-Cu turns down inflammation-driving signals, reduces cell-damaging molecules called free radicals, and turns up the activity of genes and growth factors involved in tissue repair. It also seems to help deliver copper to the right place inside cells so those copper-dependent repair enzymes can actually work. Put simply: it's a natural "cleanup and rebuild" signal that fades as we age, and giving more of it back seems to nudge damaged tissue toward repair in cells and animals.
Who should avoid it
- Anyone with Wilson's disease or another copper-metabolism/copper-overload disorder - GHK-Cu is fundamentally a copper-delivery molecule, so added copper exposure runs counter to what these conditions require, even though no study here tested this directly
- Pregnant or breastfeeding people - no safety data exists in this literature for either topical or injectable use during pregnancy or breastfeeding
- Anyone expecting injectable or high-dose GHK-Cu to be backed by human safety or efficacy data - it currently is not, per two 2026 medical reviews
- People with open, infected, or actively healing wounds - should be evaluated by a doctor rather than self-treating with peptide-containing dressings, since none of the wound-healing data here comes from human patients
Interactions to know
- No human drug-interaction studies exist for GHK-Cu in this literature.
- Copper supplements or multivitamins containing copper - combining these with GHK-Cu could theoretically add to total copper exposure, though this hasn't been studied.
- Other topical actives (retinoids, vitamin C, exfoliating acids) - commonly combined in commercial skincare, but no study here specifically tested these combinations for irritation or reduced effectiveness.
The papers that matter most
Key studies
Foundational review laying out GHK-Cu's core biology - anti-inflammatory action, boosted collagen and blood vessel growth - and summarizing older cosmetic skin studies, wound healing, and organ-protection claims. Much of the field's later research builds on this framework.
The human tri-peptide GHK and tissue remodeling.
Documents that natural blood GHK levels fall by more than half between age 20 (about 200 ng/mL) and age 60 (about 80 ng/mL), and previews early mouse research on reversing age-related cognitive decline.
The potential of GHK as an anti-aging peptide.
Real COPD patients with lower blood GHK had weaker chest muscles and more inflammation. Giving GHK-Cu to smoke-exposed mice then restored muscle mass, muscle fiber size, and grip strength - the closest thing to a human-to-animal evidence bridge in this literature.
Glycyl-l-histidyl-l-lysine-Cu2+ rescues cigarette smoking-induced skeletal muscle dysfunction via a sirtuin 1-dependent pathway.
Knee-joint injections helped ligament graft healing at 6 weeks in rats, but the benefit disappeared by 12 weeks once injections stopped - an honest illustration of GHK-Cu's limits for joint injuries.
Tripeptide-copper complex GHK-Cu (II) transiently improved healing outcome in a rat model of ACL reconstruction.
Nose-delivered GHK-Cu improved memory-test performance and lowered brain inflammation markers in aged mice over two months of daily dosing, using a delivery method the authors suggest could eventually be tested in people.
Intranasal GHK peptide enhances resilience to cognitive decline in aging mice.
States directly that while GHK-Cu shows promise for wound healing and inflammation in lab and animal work, no clinical data support its use for musculoskeletal conditions, and dosing/frequency/duration for human use remain unknown.
Injectable Peptide Therapy: A Primer for Orthopaedic and Sports Medicine Physicians.
Bottom line
GHK-Cu is a naturally occurring, well-studied molecule with a genuinely interesting and consistent story in lab dishes and animals - it calms inflammation and nudges damaged tissue toward repair almost everywhere researchers have tested it. It also has a long, reassuring safety record as a topical skincare ingredient. But beyond skin creams, the human proof is thin: one observational study links it to muscle health in COPD, and everything else - wound healing, joints, lungs, gut, brain aging - is animal or lab data only, with medical reviews confirming no clinical trials support injectable use.
Research papers
Studies we have on file for GHK-Cu. Tap a title to open it on PubMed. Labels like “animal” or “human trial” are rough guides.
40 papers
The potential of GHK as an anti-aging peptide.
GHK (glycyl-L-histidyl-L-lysine) is a naturally occurring peptide found in human serum with levels averaging 200 ng/ml at age 20 but declining to an average of 80 ng/ml by age 60. The molecule has a very high affinity for copper and forms the chelate GHK-Cu. The peptide as well as its Cu (II) chelate have anti-inflammatory and tissue remodeling properties. GHK-Cu has been shown to promote skin remodeling, wound healing and regeneration, and has prominent antioxidant and anti-inflammatory effects in in vitro and in vivo studies. In addition, preliminary observations suggest GHK can partially reverse cognitive impairment in aging mice by targeting anti-inflammatory and epigenetic pathways. The evidence as presented provides the rationale to further investigate this naturally occurring peptide in preclinical and clinical aging studies.
Regenerative and Protective Actions of the GHK-Cu Peptide in the Light of the New Gene Data.
The human peptide GHK (glycyl-l-histidyl-l-lysine) has multiple biological actions, all of which, according to our current knowledge, appear to be health positive. It stimulates blood vessel and nerve outgrowth, increases collagen, elastin, and glycosaminoglycan synthesis, as well as supports the function of dermal fibroblasts. GHK’s ability to improve tissue repair has been demonstrated for skin, lung connective tissue, boney tissue, liver, and stomach lining. GHK has also been found to possess powerful cell protective actions, such as multiple anti-cancer activities and anti-inflammatory actions, lung protection and restoration of chronic obstructive pulmonary disease (COPD) fibroblasts, suppression of molecules thought to accelerate the diseases of aging such as NFκB, anti-anxiety, anti-pain and anti-aggression activities, DNA repair, and activation of cell cleansing via the proteasome system. Recent genetic data may explain such diverse protective and healing actions of one molecule, revealing multiple biochemical pathways regulated by GHK.
Topically applied GHK as an anti-wrinkle peptide: Advantages, problems and prospective.
Peptides are promising and attractive anti-wrinkle active ingredients, amongst which glycyl-histidyl-lysine peptide (GHK) is one of the most broadly promoted peptide for topical application. This simple sequence of amino acid residues not only has the capability of tissue regeneration and the enhancement of collagen and glycosaminoglycans synthesis but also is able to increase nerve outgrowth and angiogenesis. Consequently, GHK has several properties, from wound healing to prevention/reduction wrinkles. GHK-Cu and Pal-GHK are metal complex and palmitoylated derivatives of GHK, respectively. Although GHK-Cu and Pal-GHK are widely used in anti-wrinkle products available on the cosmetic market, the published information on their skin permeability, effectiveness, physicochemical properties and so on is insufficient. This review aims to highlight whether GHK is sufficiently effective on wrinkle prevention/reduction. Apart from the effectiveness, another question that is tried to be answered is whether skin permeability of GHK allows it to act as an anti-wrinkle peptide at its site of action? Skin permeation enhancement methods employed so far are also reviewed. Based on cellular studies, undoubtedly, GHK can be considered as an anti-wrinkle ingredient. Although GHK-Cu and Pal-GHK have been of interest as effective peptides to be incorporated in the anti-wrinkle products, there is a surprising absence of clinical studies using them. Metal complexation and chemical modification with a hydrophobic moiety increase permeability of this peptide. Besides, cell penetrating peptides seem promising to increase skin permeation of GHK and its derivatives. Skin pretreatment with microneedles also has the potential to be further studied for permeation enhancement of such peptides. As peptide ingredients, their formulation may encounter some challenges, mainly due to their hydrophilic (high aqueous solubility and low partition coefficient) and unstable nature. Although GHK-Cu and Pal-GHK are effective and relatively skin permeable, their permeability could be successfully increased using permeation enhancement methodologies.
Therapeutic Peptides in Orthopaedics: Applications, Challenges, and Future Directions.
Therapeutic peptides are emerging as promising adjuncts in the management of orthopaedic injuries, grounded in their ability to modulate molecular signaling networks central to cellular medicine. By acting on key pathways such as PI3K/Akt, mTOR, MAPK, TGF-β, and AMPK, peptides exert influence over tissue regeneration, inflammation resolution, and neuromuscular recovery. Wound-healing peptides such as BPC-157, TB-500, and GHK-Cu promote angiogenesis, integrin-mediated extracellular matrix remodeling, and fibroblast activation, whereas growth hormone secretagogues like ipamorelin, CJC-1295, tesamorelin, sermorelin, and AOD-9604 activate IGF-1 signaling and satellite cell repair. Recovery-enhancing agents such as epithalon, delta sleep-inducing peptide, and pinealon target circadian and mitochondrial regulators, and neuroactive peptides like selank, semax, and dihexa enhance brain-derived neurotrophic factor and HGF/c-Met pathways critical to neuroplasticity. Although preclinical studies are promising, there is a current lack of clinical trials. This review integrates current mechanistic insights with orthopaedic relevance, emphasizing safety, efficacy, and future directions for responsible integration into musculoskeletal care.
Injectable Peptide Therapy: A Primer for Orthopaedic and Sports Medicine Physicians.
Therapeutic peptides are short-chain amino acids that regulate cellular functions and facilitate biochemical processes. In recent years, there has been significant growth in the global market for therapeutic peptides and thus its popularity among patients. Given the increase in the development of peptides and increased marketing to patients for orthopaedic injuries, it is critical for orthopaedic surgeons to understand the current evidence behind these therapeutic peptides. To evaluate the current evidence and applications of injectable peptide therapy, focusing on its potential in regenerative medicine and sports performance, to help orthopaedic providers better understand the current state of different therapeutic peptide approaches. Narrative review. A comprehensive literature search was conducted using PubMed to identify biochemical and clinical studies on the most popular types of injectable peptide therapy. Key peptides evaluated included BPC-157, TB-4, TB-500, CJC-1295 + ipamorelin, tesamorelin, and GHK-Cu. BPC-157 demonstrated potential benefits in tendon and muscle repair, but these findings are largely unvalidated in human trials. A single human case series reported improvements in pain after intra-articular knee injections of BPC-157, although significant methodological flaws and a lack of controls limit its applicability and reliability. TB-4 and its derivative TB-500 promoted angiogenesis and tissue repair in preclinical models, but human orthopaedic data are lacking, and both remain banned substances in sports. CJC-1295 combined with ipamorelin showed significantly improved maximum tetanic tension in murine models with glucocorticoid-induced muscle loss, but these findings are limited to animal studies. Tesamorelin, approved for treating HIV-associated lipodystrophy, has no supporting orthopaedic evidence. GHK-Cu showed promise in wound healing and anti-inflammatory effects, but no clinical data support its use for musculoskeletal conditions. While peptide therapy may possess significant therapeutic and regenerative potential, it is critical that orthopaedic and sports medicine providers understand the current lack of evidence to support the clinical use of these peptides. Importantly, information regarding the indications, dosing, frequency, and duration of treatment remains unknown. Despite the popularity of these peptides in mainstream media and among patients, significant research regarding the safety and efficacy of these therapeutic methods is required before definitive recommendations can be made to patients.
Glycyl-l-histidyl-l-lysine-Cu2+ rescues cigarette smoking-induced skeletal muscle dysfunction via a sirtuin 1-dependent pathway.
Skeletal muscle dysfunction is an important co-morbidity in patients with chronic obstructive pulmonary disease (COPD) and is significantly associated with increased mortality. Oxidative stress has been demonstrated an important trigger for COPD-related skeletal muscle dysfunction. Glycine-histidine-lysine (GHK) is an active tripeptide, which is a normal component of human plasma, saliva, and urine; promotes tissue regeneration; and acts as an anti-inflammatory and antioxidant properties. The purpose of this study was to determine whether GHK is involved in COPD-related skeletal muscle dysfunction. The plasma GHK level in patients with COPD (n = 9) and age-paired healthy subjects (n = 11) were detected using reversed-phase high-performance liquid chromatography. The complex GHK with Cu (GHK-Cu) was used in in vitro (C2C12 myotubes) and in vivo experiments (cigarette smoking [CS]-exposure mouse model) to explore the involvement of GHK in CS-induced skeletal muscle dysfunction. Compared with healthy control, plasma GHK levels were decreased in patients with COPD (70.27 ± 38.87 ng/mL vs. 133.0 ± 54.54 ng/mL, P = 0.009). And plasma GHK levels in patients with COPD were associated with pectoralis muscle area (R = 0.684, P = 0.042), inflammatory factor TNF-α (R = -0.696, P = 0.037), and antioxidative stress factor SOD2 (R = 0.721, P = 0.029). GHK-Cu was found to rescue CSE-induced skeletal muscle dysfunction in C2C12 myotubes, as evidenced by increased expression of myosin heavy chain, reduced expression of MuRF1 and atrogin-1, elevated mitochondrial content, and enhanced resistance to oxidative stress. In CS-induced muscle dysfunction C57BL/6 mice, GHK-Cu treatment (0.2 and 2 mg/kg) reduces CS-induced muscle mass loss (skeletal muscle weight (1.19 ± 0.09% vs. 1.29 ± 0.06%, 1.40 ± 0.05%; P < 0.05) and muscle cross-sectional area elevated (1055 ± 552.4 μm2 vs. 1797 ± 620.9 μm2 , 2252 ± 534.0 μm2 ; P < 0.001), and also rescues CS-induced muscle weakness, indicated by improved grip strength (175.5 ± 36.15 g vs. 257.6 ± 37.98 g, 339.1 ± 72.22 g; P < 0.01). Mechanistically, GHK-Cu directly binds and activates SIRT1(the binding energy was -6.1 kcal/mol). Through activating SIRT1 deacetylation, GHK-Cu inhibits FoxO3a transcriptional activity to reduce protein degradation, deacetylates Nrf2 and contribute to its action of reducing oxidative stress by generation of anti-oxidant enzymes, increases PGC-1α expression to promote mitochondrial function. Finally, GHK-Cu could protect mice against CS-induced skeletal muscle dysfunction via SIRT1. Plasma glycyl-l-histidyl-l-lysine level in patients with chronic obstructive pulmonary disease was significantly decreased and was significantly associated with skeletal muscle mass. Exogenous administration of glycyl-l-histidyl-l-lysine-Cu2+ could protect against cigarette smoking-induced skeletal muscle dysfunction via sirtuin 1.
Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance.
Peptides are short chains of amino acids with a unique pharmacological niche between small-molecule drugs and large proteins. Their use in sports medicine is rapidly expanding, driven by patient demand for accelerated injury recovery and performance enhancement. While numerous peptide drugs have undergone a rigorous approval process that evaluates both safety and efficacy, a parallel "gray market" of unapproved compounds has emerged, operating largely outside of regulatory oversight. Our objective is to present the pharmacological mechanisms, safety profiles, and regulatory status of prominent approved and unapproved peptides marketed direct to patients, including AOD-9604 (anti-obesity drug 9604), BPC-157 (body protection compound 157), CJC-1295, FS-344 (follistatin-344), GHK-Cu (glycyl-L-histidyl-L-lysine copper), ipamorelin, MOTS-C (mitochondrial ORF of the 12S rRNA type-c), sermorelin, SS-31 (elamipretide), tesamorelin (Egrifta), Tβ4 (thymosin beta-4), and TB-500 (thymosin beta-4 fragment). Many unapproved peptides demonstrate favorable tissue repair and metabolic outcomes in animal models, but rigorous human safety data are scarce, and there is potential for serious harm to patients. This narrative review focuses on the utilization of peptides in sports medicine, and alternative treatments that may be considered. We provide a framework to navigate patient discussions about peptides to better facilitate evidence-based practices for musculoskeletal healing and athletic performance. We also discuss the placebo effect as a mediator of peptide efficacy, and how social media amplifies this effect.
An injectable hydroxyapatite microsphere filler loaded with GHK-Cu tripeptide for anti-Inflammatory and antioxidant.
With the wide application of soft tissue fillers, implant material-induced inflammatory reactions have become a key factor affecting the therapeutic efficacy. This study developed an injectable filler with enhanced anti-inflammatory and antioxidant effects by adsorbing glycyl-L-histidyl-L-lysine copper complex (GHK-Cu) onto hydroxyapatite microspheres (HAPs), marking the first combination of HAPs and GHK-Cu to address inflammation caused by soft tissue fillers. GHK-Cu was successfully loaded onto HAPs by electrostatic adsorption. HAPs were then mixed with carboxymethyl cellulose (CMC), glycerol (GLY), and water to form GHK-Cu@CMHA gel. The study focus on the effective combination of HAPs as a carrier for sustained GHK-Cu delivery and the anti-inflammatory properties of GHK-Cu. GHK-Cu@CMHA exhibits sustained release properties for 7 days, which ensures prolonged therapeutic effects, minimizes peptide waste and reduces injection frequency, with good flowability and injectability. In the model of LPS-induced inflammation model in vivo and in vitro, GHK-Cu@CMHA gel reduced levels of inflammatory factors and Reactive oxygen species (ROS) levels decreased, while superoxide dismutase (SOD) activity was enhanced. In this process, H&E staining and Masson staining revealed significant collagen deposition. These findings further confirm that GHK-Cu@CMHA is a novel injectable soft tissue filler with good anti-inflammatory and antioxidant properties, which holds well potential for inflammation inhibition.
Phenothiazine-Based Cu(II)-Selective Fluorescent Sensor: GHK-Cu Sensing Applications.
Sensing important metals in different environments is an important area and involves the development of a wide variety of metal-sensing materials. The employment of fluorescent sensors in metal sensing has been one of the most widely applied methodologies, and the identification of selective metal sensors is important. We herein report a phenothiazine-based Cu(II) fluorescent sensor that is highly selective to Cu(II) ions compared with other transition metal salts. The Lewis acidity of the Cu(II) salt certainly was found to be a factor for obtaining an enhanced sensing response in MeOH as the solvent, while a ratio of 1:1 was calculated to be the most optimum for getting the desired response.
Tripeptide-copper complex GHK-Cu (II) transiently improved healing outcome in a rat model of ACL reconstruction.
After anterior cruciate ligament reconstruction (ACLR), the biological healing of the graft is a rate-limiting step which can contribute to graft failure. The tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu(II) (GHK-Cu) is a well-known activator of tissue remodeling. We investigated whether GHK-Cu can improve graft healing following ACLR. Seventy-two rats underwent unilateral ACLR were randomized to saline, 0.3 or 3 mg/ml GHK-Cu groups (n = 24). Post-operational intra-articular injections were given from week 2, once a week, for 4 weeks. Gait analysis was performed pre-injury and at harvesting time. At 6 or 12 weeks post-operation, knee specimens were harvested for knee laxity test, graft pull-out test, and histology. At 6 weeks post-ACLR, GHK-Cu groups resulted in a smaller side-to-side difference in knee laxity as compared to the saline group (p = 0.009), but there was no significant difference at 12 weeks post-operation. The graft complex in the 0.3 mg/ml GHK-Cu group had higher stiffness than saline group at 6 weeks post-operation (p = 0.026), but there was no significant difference in ultimate load, gait parameters, and histological scores among treatment groups. All grafts failed mid-substance during pull-out test. Intra-articular supplementation with a bioactive small molecule GHK-Cu improved graft healing following ACLR in rat, but the beneficial effects could not last as treatment discontinued.
The glycyl-l-histidyl-l-lysine-Cu2+ tripeptide complex attenuates lung inflammation and fibrosis in silicosis by targeting peroxiredoxin 6.
Silicosis is the most common type of pneumoconiosis, having a high incidence in workers chronically exposed to crystalline silica (CS). No specific medication exists for this condition. GHK, a tripeptide naturally occurring in human blood and urine, has antioxidant effects. We aimed to investigate the therapeutic effect of GHK-Cu on silicosis and its potential underlying molecular mechanism. An experimental silicosis mouse model was established to observe the effects of GHK-Cu on lung inflammation and fibrosis. Moreover, the effects of GHK-Cu on the alveolar macrophages (AM) were examined using the RAW264.7 cell line. Its molecular target, peroxiredoxin 6 (PRDX6), has been identified, and GHK-Cu can bind to PRDX6, thus attenuating lung inflammation and fibrosis in silicosis mice without significant systemic toxicity. These effects were partly related to the inhibition of the CS-induced oxidative stress in AM induced by GHK-Cu. Thus, our results suggest that GHK-Cu acts as a potential drug by attenuating alveolar macrophage oxidative stress. This, in turn, attenuates the progression of pulmonary inflammation and fibrosis, which provides a reference for the treatment of silicosis.
Exploring the beneficial effects of GHK-Cu on an experimental model of colitis and the underlying mechanisms.
Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) characterized by mucosal damage and impaired epithelial barrier function. While glycyl-l-histidyl-l-lysine-copper (GHK-Cu) exhibits known anti-inflammatory properties, its therapeutic mechanisms in UC remain undefined. This study was designed to systematically evaluate the therapeutic potential of GHK-Cu in a dextran sulfate sodium (DSS)-induced murine model of UC, with particular emphasis on elucidating its regulatory effects on the NAD-dependent deacetylase sirtuin-1 (SIRT1)/signal transducer and activator of transcription 3 (STAT3) signaling pathway. UC was induced in BALB/c mice with 3% DSS for 14 days. The protein expression levels of tight junction associated protein-1 (ZO-1), Occludin, inflammatory factors interleukin (IL)-6, IL-1β and tumor necrosis factor (TNF)-α, SIRT1, STAT3, p-STAT3, and retinoic acid receptor-related orphan receptor gamma t (RORγt) were detected by Western blot. Histopathological changes were evaluated by Hematoxylin and Eosin (H&E) and Alcian blue-periodic acid-Schiff (AB-PAS). Network pharmacology and molecular docking were used to predict the core targets of GHK Cu in the treatment of UC. An in vitro UC model was also established in mouse peritoneal macrophages (MPMs) using lipopolysaccharide (LPS), and a co culture model was constructed using mouse colonic epithelial cells (MCECs) and MPMs to examine the role of GHK Cu in promoting mucosal healing. STAT3 was silenced by gene transfection technology to verify the core role of STAT3 in GHK Cu treatment of UC. GHK-Cu alleviated weight loss, improved the disease activity index (DAI), reduced colonic edema and shortening, attenuated inflammatory damage, increased goblet cell numbers, suppressed inflammatory cytokines such as TNF-α, IL-6, and IL-1β, and promoted mucosal repair. Additionally, a co-culture system of MCECs and MPMs revealed that GHK-Cu facilitated MCECs healing, impaired by DSS, by upregulating ZO-1 and Occludin expression. Subsequently, network pharmacology and molecular docking identified SIRT1 as a potential target of GHK-Cu. Results showed that GHK-Cu upregulated SIRT1 protein expression and suppressed the expression of phosphorylated p-STAT3 in colon tissue and MCECs of the co-culture model. Our findings revealed that after transfection with STAT3-targeting siRNA (siSTAT3), the stimulant effect of GHK-Cu on the healing of MCECs and the effect on the protein expression of ZO-1 and Occludin is canceled. Nevertheless, after transfection with siSTAT3, it could inhibit the expression of inflammatory factors in conjunction with GHK-Cu. Furthermore, we found that GHK-Cu could inhibit RORγt expression in the colon tissue of UC mice. This study found that GHK-Cu demonstrated significant therapeutic effects in DSS-induced UC in mice. GHK-Cu may promote mucosal healing and enhance tight junction protein expression by regulating the SIRT1/STAT3 pathway. In addition to suppressing p-STAT3 expression, GHK-Cu may utilize additional pathways to inhibit inflammatory factors. Furthermore, GHK-Cu may reduce the number of Th17 cells. In summary, GHK-Cu may treat UC by acting on the SIRT1/STAT3 pathway.
Are We Ready to Measure Skin Permeation of Modern Antiaging GHK-Cu Tripeptide Encapsulated in Liposomes?
Cosmetically active compounds (CACs), both of lipophilic and hydrophilic origin, have difficulty reaching the deeper layers of the skin, and this shortcoming significantly reduces their efficacy. One such CAC that occurs naturally in the human body and displays many beneficial properties (via reducing fine lines and wrinkles, tightening skin, improving its elasticity, etc.) is the glycyl-L-histidyl-L-lysine tripeptide complex of copper (GHK-Cu). GHK-Cu is a fairly hydrophilic compound with limited permeation through the lipophilic stratum corneum. On the other hand, liposomes capable of encapsulating GHK-Cu may improve its permeation potential. The present review discusses various issues related to obtaining insight into the permeation of CACs through the skin. Methods for studying the transport of CACs encapsulated by liposomes and free GHK-Cu across the skin barrier are summarized. An analysis of the literature data reveals that the transport of liposomes containing GHK-Cu received little attention. This research gap gives an impetus to the methodological developments for assessing the effect of liposomes on GHK-Cu transportation and trafficking.
Liposomes as Carriers of GHK-Cu Tripeptide for Cosmetic Application.
Liposomes are self-assembled spherical systems composed of amphiphilic phospholipids. They can be used as carriers of both hydrophobic and hydrophilic substances, such as the anti-aging and wound-healing copper-binding peptide, GHK-Cu (glycyl-L-histidyl-L-lysine). Anionic (AL) and cationic (CL) hydrogenated lecithin-based liposomes were obtained as GHK-Cu skin delivery systems using the thin-film hydration method combined with freeze-thaw cycles and the extrusion process. The influence of total lipid content, lipid composition and GHK-Cu concentration on the physicochemical properties of liposomes was studied. The lipid bilayer fluidity and the peptide encapsulation efficiency (EE) were also determined. Moreover, in vitro assays of tyrosinase and elastase inhibition were performed. Stable GHK-Cu-loaded liposome systems of small sizes (approx. 100 nm) were obtained. The bilayer fluidity was higher in the case of cationic liposomes. As the best carriers, 25 mg/cm3 CL and AL hydrated with 0.5 mg/cm3 GHK-Cu were selected with EE of 31.7 ± 0.9% and 20.0 ± 2.8%, respectively. The obtained results confirmed that the liposomes can be used as carriers for biomimetic peptides such as copper-binding peptide and that the GHK-Cu did not significantly affect the tyrosinase activity but led to 48.90 ± 2.50% elastase inhibition, thus reducing the rate of elastin degeneration and supporting the structural integrity of the skin.
Copper Complexes with New Glycyl-l-histidyl-l-lysine-Hyaluronan Conjugates Show Antioxidant Properties and Osteogenic and Angiogenic Synergistic Effects.
In recent years, hyaluronic acid (HA) and the natural tripeptide glycyl-l-histidyl-l-lysine (GHK), especially its copper(II) complex (GHK-Cu), individually have been shown to exert helpful properties for bone protection and regeneration. However, they are not strong enough to handle oxidative stress, hydrolytic attack, or environmental conditions. Being aware that conjugation chemistry has recently emerged as an appealing approach for generating new molecular entities capable of preserving the molecular integrity of their moieties or delaying their degradation, herein we present the synthesis of conjugates of HA with GHK (GHK-HA), at different loadings of the tripeptide. GHK-HA binds copper(II) ions and potentiates the chemical and biological properties of the two components in in vitro assays. The results highlight copper's role in promoting the expression and release of certain trophic, angiogenic, and osteogenic factors, including brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor (VEGF), as well as bone morphogenetic protein-2 (BMP-2). The protective and regenerative activities of the metal ion are related to the translocation of its intracellular chaperones Copper Chaperone for Superoxide Dismutase (CCS) and Antioxidant-1 (Atox1) to the nucleus where they act as transcription factors.
The human tri-peptide GHK and tissue remodeling.
Tissue remodeling follows the initial phase of wound healing and stops inflammatory and scar-forming processes, then restores the normal tissue morphology. The human peptide Gly-(L-His)-(L-Lys) or GHK, has a copper 2+ (Cu(2+)) affinity similar to the copper transport site on albumin and forms GHK-Cu, a complex with Cu(2+). These two molecules activate a plethora of remodeling related processes: (1) chemoattraction of repair cells such as macrophages, mast cells, capillary cells; (2) anti-inflammatory actions (suppression of free radicals, thromboxane formation, release of oxidizing iron, transforming growth factor beta-1, tumor necrosis factor alpha and protein glycation while increasing superoxide dismutase, vessel vasodilation, blocking ultraviolet damage to skin keratinocytes and improving fibroblast recovery after X-ray treatments); (3) increases protein synthesis of collagen, elastin, metalloproteinases, anti-proteases, vascular endothelial growth factor, fibroblast growth factor 2, nerve growth factor, neutrotropins 3 and 4, and erythropoietin; (4) increases the proliferation of fibroblasts and keratinocytes; nerve outgrowth, angiogenesis, and hair follicle size. GHK-Cu stimulates wound healing in numerous models and in humans. Controlled studies on aged skin demonstrated that it tightens skin, improves elasticity and firmness, reduces fine lines, wrinkles, photodamage and hyperpigmentation. GHK-Cu also improves hair transplant success, protects hepatic tissue from tetrachloromethane poisoning, blocks stomach ulcer development, and heals intestinal ulcers and bone tissue. These results are beginning to define the complex biochemical processes that regulate tissue remodeling.
Ultrasensitive and Label-Free Detection of Copper Ions by GHK-Modified Asymmetric Nanochannels.
Artificial solid-state nanochannels have garnered considerable attention as promising nanofluidic tools for ion/molecular detection, DNA sequencing, and biomimicry. Recently, nanofluidic devices have emerged as cost-effective detection tools for heavy metal ions by modifying stimuli-responsive materials. In this work, high-purity glycyl-l-histidyl-l-lysine (GHK) peptide is synthesized by using 7-diphenylphosphonooxycoumarin-4-methanol (DPCM) as a protecting group and auxiliary carrier by homogeneous synthesis of photocleavable groups. Subsequently, we developed a GHK-modified asymmetric nanochannel nanofluidic diode by covalently attaching the GHK peptide to the inner surface of the nanochannels. This modification facilitated specific recognition and ultra-trace level detection of Cu2+ ions, achieving a detection limit of 10-15 M. Due to the robust complexing ability between Cu2+ and GHK peptide, the GHK-modified asymmetric nanochannels can form GHK-Cu complexes on the inner surface of nanochannels when Cu2+ passes through the nanochannels. This results in changes of current-potential (I-V) properties, which facilitated Cu2+ detection. Theoretical calculations confirmed the high affinity of the GHK peptide for Cu2+, thereby ensuring excellent Cu2+ selectivity. To evaluate the applicability of our system for detecting Cu2+ in real-world scenarios, we analyzed the concentration of Cu2+ in tap water. The GHK-Cu complexes could be dissociated by adding EDTA to the solution, enabling the regeneration and reuse of this ultrasensitive and label-free Cu2+ detection system using GHK-modified asymmetric multi-nanochannels. We anticipate that the GHK-modified asymmetric nanochannels will find future applications in the label-free detection of Cu2+ in domestic water.
The human tripeptide GHK-Cu in prevention of oxidative stress and degenerative conditions of aging: implications for cognitive health.
Oxidative stress, disrupted copper homeostasis, and neuroinflammation due to overproduction of proinflammatory cytokines are considered leading causative factors in development of age-associated neurodegenerative conditions. Recently, a new mechanism of aging-detrimental epigenetic modifications-has emerged. Thus, compounds that possess antioxidant, anti-inflammatory activity as well as compounds capable of restoring copper balance and proper gene functioning may be able to prevent age-associated cognitive decline and ward off many common neurodegenerative conditions. The aim of this paper is to bring attention to a compound with a long history of safe use in wound healing and antiaging skin care. The human tripeptide GHK was discovered in 1973 as an activity in human albumin that caused old human liver tissue to synthesize proteins like younger tissue. It has high affinity for copper ions and easily forms a copper complex or GHK-Cu. In addition, GHK possesses a plethora of other regenerative and protective actions including antioxidant, anti-inflammatory, and wound healing properties. Recent studies revealed its ability to up- and downregulate a large number of human genes including those that are critical for neuronal development and maintenance. We propose GHK tripeptide as a possible therapeutic agent against age-associated neurodegeneration and cognitive decline.
Glycyl-L-histidyl-L-lysine-Cu2+ (GHK-Cu) Attenuates CuSO4 or LPS induced-inflammation in Zebrafish larvae model.
Inflammation serves as a basic defense mechanism against both internal and external threats, while the unresolved or excessive inflammation can lead to irreversible tissue damage. Glycyl-L-histidyl-L-lysine-Cu2+ (GHK-Cu), a bioactive tripeptide complex known for its anti-aging and tissue repair properties, is extensively utilized in dermatological and hair care formulations. However, the role of GHK-Cu in regulating inflammation is less known. In this study, we explored the anti-inflammatory effects of GHK-Cu against the acute inflammation induced by copper sulfate (CuSO4) and lipopolysaccharide (LPS) in zebrafish larvae. GHK-Cu notably decreased the migration of neutrophils and macrophages, suppressed the expression of pro-inflammatory cytokines (tnf-a, il-1β, il6) and increased the expression of the anti-inflammatory cytokine il-10. Moreover, GHK-Cu mitigated oxidative stress by reducing levels of nitric oxide (NO) and reactive oxygen species (ROS), and improved superoxide dismutase (SOD) activity. Furthermore, pathway analysis revealed that GHK-Cu administration downregulated the JAK1 pathway. In summary, this study highlights the dual role of GHK-Cu in both anti-inflammatory and anti-oxidant properties, which provides the theoretical evidences supporting its addition as a functional cosmetic ingredient.
Food-Derived Tripeptide-Copper Self-Healing Hydrogel for Infected Wound Healing.
The field of infected wound management continues to face challenges, and traditional methods used to cope with wounds include debridement, gauze coverage, medication, and others. Currently, synthetic and natural biomaterials are readily available today, enabling the creation of new wound dressings that substantially enhance wound healing. Considerable attention is being paid to hydrogels based on natural materials, which have good biocompatibility and degradability properties, while exhibiting higher similarity to natural extracellular matrix as compared to synthetic materials. In this study, we extracted the active ingredients of oxidized konjac glucomannan (OKGM) and fresh egg white (EW) from 2 foods, konjac, and egg, respectively, and formed a self-repairing hydrogel based on the cross-linking of a Schiff base. Subsequently, a natural active peptide, glycyl-l-histidyl-l-lysine-Cu (GHK-Cu), was loaded, and an all-natural composite hydrogel dressing, EW/OKGM@GHK-Cu (GEK), was developed. The GEK hydrogel, exhibiting both antibacterial and anti-inflammatory properties, plays a hemostatic role by adhering to tissues and promoting neovascularization and serves as an optimal dressing for skin regeneration. Taken together, GEK hydrogel dressings derived from natural food sources therefore constitute an efficient and cost-effective strategy for managing infected wound healing and have significant potential for clinical application and transformation.
Therapeutic Peptides in Aesthetic, Metabolic and Endocrine Conditions: Effects, Safety, Clinical Applications, and Future Perspectives.
Therapeutic peptides are short chains of amino acids used to treat metabolic and endocrine conditions such as obesity and type 2 diabetes. While several peptide drugs have undergone rigorous approval processes that evaluate both safety and efficacy, novel, unapproved compounds have emerged and are rapidly expanding into preventive medicine and performance enhancement. Our objective is to present the effects, clinical applications, safety profiles, and regulatory status of prominent peptides used to treat several conditions. We reviewed 106 articles, prioritizing systematic reviews, meta-analyses, and randomized controlled trials in the PubMed, ScienceDirect, and SciELO databases. Our results suggest that therapeutic peptides are a promising tool for treating type 2 diabetes and obesity, for skin rejuvenation, and as hormone analogs for specific diseases and conditions. Although these are strategic and innovative options that can improve health, performance, and longevity, further studies are needed before most new peptides can be used safely in humans.
GHK-Cu-liposomes accelerate scald wound healing in mice by promoting cell proliferation and angiogenesis.
Glycyl-l-histidyl-l-lysine (GHK)-Cu is considered to be an activator of tissue remodeling, and has been used in cosmetic products. In this study, we prepared liposomes encapsulating GHK-Cu and analyzed their effect on human umbilical vein endothelial cells (HUVECs) proliferation and scald wound healing in mice. The nanoscaled GHK-Cu-liposomes promoted HUVECs proliferation, with a 33.1% increased rate. Flow cytometry analysis showed increased cell number at G1 stage and decreased cell number at G2 stage after GHK-Cu-liposomes treatment. Western blotting indicated that the expression of vascular endothelial growth factor and fibroblast grow factors-2 were both enhanced, as well as cell cycle-related proteins CDK4 and CyclinD1. In a mice scald model, angiogenesis in burned skin treated with GHK-Cu-liposomes was better compared with free GHK-Cu, and immunofluorescence analysis showed enhanced signal of CD31 and Ki67 in GHK-Cu-liposomes treated mice. Moreover, the wound healing time was shortened to 14 days post injury. Our results provide the evidence that GHK-Cu-liposomes could be utilized as a treatment for skin wounds.
Protective effects of GHK-Cu in bleomycin-induced pulmonary fibrosis via anti-oxidative stress and anti-inflammation pathways.
Idiopathic pulmonary fibrosis (IPF) is a serious lung problem with advancing and diffusive pulmonary fibrosis as the pathologic basis, and with oxidative stress and inflammation as the key pathogenesis. Glycyl-L-histidyl-l-lysine (GHK) is a tripeptide participating into wound healing and regeneration. GHK-Cu complexes improve GHK bioavailability. Thus, the current study aimed to explore the therapeutic role of GHK-Cu on bleomycin (BLM)-induced pulmonary fibrosis in a mouse model. BLM (3 mg/kg) was administered via tracheal instillation (TI) to induce a pulmonary fibrosis model in C57BL/6j mice 21 days after the challenge of BLM. GHK-Cu was injected intraperitoneally (i.p.) at different dosage of 0.2, 2 and 20 μg/g/day in 0.5 ml PBS on alternate day. The histological changes, inflammation response, the collagen deposition and epithelial-mesenchymal transition (EMT) was evaluated in the lung tissue. EMT was evaluated by ɑ-SMA and fibronectin expression in the lung tissue. NF-κB p65, Nrf2 and TGFβ1/Smad2/3 signalling pathways were detected by immunoblotting analysis. GHK-Cu complex inhibited BLM-induced inflammatory and fibrotic pathological changes, alleviated the inflammatory response in the BALF by reducing the levels of the inflammatory cytokines, TNF-ɑ and IL-6 and the activity of MPO as well as reduced collagen deposition. In addition, the GHK-Cu treatment significantly reversed the MMP-9/TIMP-1 imbalance and partially prevented EMT via Nrf2, NF-κB and TGFβ1 pathways, as well as Smad2/3 phosphorylation. GHK-Cu presented a protective effect in BLM-induced inflammation and oxidative stress by inhibiting EMT progression and suppressing TGFβ1/Smad2/3 signalling in pulmonary fibrosis.
Golgi-targeted copper delivery strategy via enhancing copper-dependent proteins' activity for fascia regeneration.
Copper-dependent proteins (such as lysyl oxidase, LOX) require copper acquisition within the Golgi apparatus to achieve enzymatic activation, and insufficient activation of these proteins is a key factor limiting fascia regeneration. To address this issue, this study, for the first time, proposes and validates a Golgi-targeted copper delivery system (LNP-ATOX1/GHK-Cu@PCL-GelMA). In this system, GHK-Cu serves as a stable copper source to provide a sustained release of Cu ions for cellular uptake, while lipid nanoparticles (LNPs) are used to deliver mRNA encoding the copper chaperone ATOX1. Upregulation of ATOX1 facilitates the transport of copper into the Golgi apparatus via ATP7A/B, thereby enhancing the activity of copper-dependent proteins. In addition, ATOX1 promotes the copper-dependent translocation of ATP7A and Rac1 to the plasma membrane, synergistically accelerating neovascularization. In vitro studies demonstrated that this material system significantly increased copper accumulation within the Golgi apparatus, elevated LOX activity to 1.78 times that of the control group, and enhanced angiogenic capacity. In a rabbit fascia defect model, this strategy effectively promoted collagen alignment and neovascularization, improving extracellular matrix reconstruction and facilitating fascia regeneration. In conclusion, this work establishes a novel Golgi-targeted copper delivery strategy, providing a practical therapeutic approach for regenerative disorders caused by insufficient activation of copper-dependent proteins, such as fascia defects.
Glycyl-L-histidyl-L-lysine-Cu2+ attenuates cigarette smoke-induced pulmonary emphysema and inflammation by reducing oxidative stress pathway.
Background: Chronic obstructive pulmonary disease (COPD) is a common respiratory disorder manifested as chronic airway inflammation and persistent airflow limitation with the essential mechanism as inflammatory response and oxidative stress induced by toxic exposures such as cigarette smoke (CS). Glycyl-L-histidyl-L-lysine (GHK) is a nontoxic tripeptide involved in the process of healing and regeneration as a natural product. With the combination of Cu(II), glycyl-L-histidyl-L-lysine-Cu2+ (GHK-Cu) improves antioxidative and anti-inflammatory bioavailability, and they might offer potential therapeutic properties for COPD. Thus, the present study aimed to identify the potential effects of GHK-Cu on emphysema induced by cigarette smoke. Methods: In the in vivo experiment, C57BL/6J mice were exposed to CS for 12 weeks to induce pulmonary emphysema. GHK-Cu was injected intraperitoneally at doses of 0.2, 2 and 20 μg/g/day in 100 µl of saline on alternative days from the 1st day after CS exposure. The effects of GHK-Cu on the morphology of CS-induced emphysema, the inflammatory response and oxidative stress were evaluated. The antioxidative effect of GHK-Cu on human alveolar epithelial A549 cells was assessed in vitro. Results: GHK-Cu treatment attenuated the CS-induced emphysematous changes and partially reversed the matrix metalloprotein -9 (MMP-9)/tissue inhibitor of metalloproteinases-1 (TIMP-1) imbalance in the lung tissue. GHK-Cu reduced the inflammation and oxidation by decreasing the expression of inflammatory cytokines (IL-1β and TNF-α) in the bronchoalveolar lavage and the enzymatic activity of MPO and MDA in the lung homogenate while restoring the T-AOC and GSH content. Furthermore, administration of GHK-Cu reversed the increase in NF-κB expression induced by CS and increased the Nrf2 level, as an antioxidant defense component, in mice with chronic CS exposure. In CSE-exposed human alveolar epithelial A549 cells, GHK-Cu also inhibited oxidative stress by suppressing MDA levels and restoring T-AOC and GSH levels, which were modulated by upregulating Nrf2 expression. Conclusion: GHK-Cu treatment attenuated CS-induced emphysema by anti-inflammation by downregulating NF-κB and antioxidation via upregulation of the Nrf2/Keap1 in lung tissues.
Thermodynamically stable ionic liquid microemulsions pioneer pathways for topical delivery and peptide application.
Copper peptides (GHK-Cu) are a powerful hair growth promoter with minimal side effects when compared with minoxidil and finasteride; however, challenges in delivering GHK-Cu topically limits their non-invasive applications. Using theoretical calculations and pseudo-ternary phase diagrams, we designed and constructed a thermodynamically stable ionic liquid (IL)-based microemulsion (IL-M), which integrates the high drug solubility of ILs and high skin permeability of microemulsions, thus improving the local delivery of copper peptides by approximately three-fold while retaining their biological function. Experiments in mice validated the effectiveness of our proposed IL-M system. Furthermore, the exact effects of the IL-M system on the expression of growth factors, such as vascular endothelial growth factor, were revealed, and it was found that microemulsion increased the activation of the Wnt/β-catenin signaling pathway, which includes factors involved in hair growth regulation. Overall, the safe and non-invasive IL microemulsion system developed in this study has great potential for the clinical treatment of hair loss.
Intranasal GHK peptide enhances resilience to cognitive decline in aging mice.
Brain aging and cognitive decline are aspects of growing old. Age-related cognitive impairment entails the early stages of cognitive decline, and is extremely common, affecting millions of older people. Investigation into early cognitive decline as a treatable condition is relevant to a wide range of cognitive impairment conditions, since mild age-related neuropathology increases risk for more severe neuropathology and dementia associated with Alzheimer's Disease. Recent studies suggest that the naturally occurring peptide GHK (glycyl-L-histidyl-L-lysine) in its Cu-bound form, has the potential to treat cognitive decline associated with aging. In order to test this concept, male and female C57BL/6 mice, 20 months of age, were given intranasal GHK-Cu, 15 mg/kg daily, for two months. Results showed that mice treated with intranasal GHK-Cu had an enhanced level of cognitive performance in spatial memory and learning navigation tasks, and expressed decreased neuroinflammatory and axonal damage markers compared to mice treated with intranasal saline. These observations suggest that GHK-Cu can enhance resilience to brain aging, and has translational implications for further testing in both preclinical and clinical studies using an atomizer device for intranasal delivery.
Microenvironment-responsive injectable dynamic hydrogel for sequential antioxidant and tissue regeneration therapy of radiation-induced skin injury.
Radiotherapy is essential for cancer treatment, yet radiation-induced skin injury (RISI) remains a major clinical challenge due to reactive oxygen species (ROS) accumulation, metabolic dysregulation, and the limited efficacy of single-modality therapies in modulating the oxidative-inflammatory microenvironment. To overcome this limitation, we have developed a multifunctional injectable hydrogel, HCG@CDs, by cross-linking biocompatible carboxymethyl chitosan (CMCS) with oxidized hyaluronic acid (OHA) conjugated to the Glycyl-L-Histidyl-L-Lysine-Copper(II) complex (GHK-Cu 2 + ) via dynamic Schiff-base linkages. Carbon dots (CDs) possessing superoxide dismutase (SOD)-like activity are uniformly dispersed within this three-dimensional dynamic network, creating an integrated platform for full-cycle therapy. The system exhibits intelligent, pH-responsive release behavior, whereby CDs are rapidly liberated in the acidic wound microenvironment to efficiently scavenge ROS and mitigate early-stage oxidative stress. Subsequently, GHK-Cu 2 + is released in a sustained manner to synergistically promote tissue repair by modulating inflammation, enhancing cell migration and proliferation, and facilitating collagen deposition. In vitro and in vivo evaluations have confirmed that the HCG@CDs hydrogel effectively alleviates radiation-induced oxidative damage and inflammatory responses, significantly accelerating the healing of skin wounds. Overall, this multifunctional hydrogel demonstrates great potential in accelerating the healing of RISI through multi-target synergistic regulation, highlighting its significant promise for clinical wound management and skin regeneration.
Microneedle-Mediated Delivery of Copper Peptide Through Skin.
Copper peptide (GHK-Cu) plays an important role in skin regeneration and wound healing. However, its skin absorption remains challenging due to its hydrophilicity. Here we use polymeric microneedle array to pre-treat skin to enhance GHK-Cu skin penetration. Two in vitro skin models were used to assess the capability of microneedles in facilitating skin delivery of GHK-Cu. Histological assay and confocal laser scanning microscopy were performed to characterize and quantify the microconduits created by the microneedles inside skin. Cellular and porcine models were used to evaluate the safety of microneedle-assisted copper peptide delivery. The depth and percentage of microneedle penetration were correlated with application forces, which in turn influenced the extent of enhancement in the skin permeability of GHK-Cu. In 9 h, 134 ± 12 nanomoles of peptide and 705 ± 84 nanomoles of copper permeated though the microneedle treated human skin, while almost no peptide or copper permeated through intact human skin. No obvious signs of skin irritation were observed with the use of GHK-Cu after microneedle pretreatment. It is effective and safe to enhance the skin permeation of GHK-Cu by using microneedles. This approach may be useful to deliver similar peptides or minerals through skin.
Synergy of GHK-Cu and hyaluronic acid on collagen IV upregulation via fibroblast and ex-vivo skin tests.
GHK-Cu and HA are two commonly used skin care ingredients, both of which were reported to enhance collagen synthesis. This work aims to investigate their co-effect on collagen regulation. In cell experiments, human dermal fibroblasts were treated by a series of GHK-Cu and HA combinations, and the expressions of collagen I, IV, and VII were measured by qRT-PCR. The best formula screened out from cell experiments were further studied by ex-vivo skin model, and the content of collagen IV was quantified by immunofluorescence method. The combination GHK-Cu and HA was found to promote the generation of collagen I, IV, and VII. Especially, they form a synergy on collagen IV. At the ratio of 1:9, GHK-Cu and LMW HA deliver the strongest effect to elevate collagen IV synthesis by 25.4 times in cell test and 2.03 times in ex-vivo skin test. The co-effect of GHK-Cu and HA was revealed. Their synergy brings an insight to anti-aging technology: choosing proper molecular weight of HA and managing its ratio with GHK-Cu could enhance DEJ health via stimulating collagen IV synthesis.
Electrophoretic deposition of GHK-Cu loaded MSN-chitosan coatings with pH-responsive release of copper and its bioactivity.
Despite the fact that titanium has been widely applied in the replacement of bone defects, prosthesis failure still occurred because of the lack of adequate bone-bonding ability and the incidence of post-surgery infections. Concentration-dependent effects of therapeutic copper ions (Cu2+) for antibacterial and osteogenic activity have been well-established in the field of biomedical application. In this study, we prepared mesoporous silica nanoparticles (MSN) and MSN-COOH with uniform sphere size (~100 nm) and developed multifunctional chitosan coatings loaded with MSN@GHK-Cu (glycyl-L-histidyl-l-lysine-Cu2+) as a suitable strategy by electrophoretic deposition (EPD). The microstructure and composition of the coating were comprehensively characterized by using SEM, XRD, FTIR, and TEM, respectively. The functional activity of Cu2+ releasing from the surface was dependent on the pH value of the titanium surface. Through the controllable release of Cu2+, the coating achieved not only inhibited adhesion of bacteria but also had good cytocompatibility. The coating based on EPD technique could be considered as a promising surface modification approach for the controlled delivery in situ of drug or other biomolecules.
Novel Applications of CE-ICP-MS/MS: Monitoring of Antiaging GHK-Cu Cosmetic Component Encapsulation in Liposomes.
The hyphenation of the separation technique with the high-sensitive mass spectrometry detection is one of the driving forces of modern analysis enabling measurements in complex matrices. In particular, capillary electrophoresis coupled to inductively coupled plasma tandem mass spectrometry allows for speciation analysis of selected analytes with a superior resolution. The mild, physiological-friendly conditions of this separation technique offer the unique advantage of analyzing chemical entities in their intact form, which has been successfully exploited in various areas. Herein, we report the pioneering application of such a hyphenated technique in the cosmetic field to investigate the encapsulation of copper tripeptide complex (GHK-Cu) in liposomes. By monitoring copper and phosphorus signals, the formation of liposomes via a simple ethanol injection method was confirmed, and the concentration of GHK-Cu in the liposomes was assessed. The application of coupling of capillary electrophoresis with inductively coupled plasma tandem mass spectrometry (CE-ICP-MS/MS) in cosmetic studies could lead to the development of diverse liposomal formulations with preferential properties and expand their accessibility.
Ternary Cu(II) Complex with GHK Peptide and Cis-Urocanic Acid as a Potential Physiologically Functional Copper Chelate.
The tripeptide NH2-Gly-His-Lys-COOH (GHK), cis-urocanic acid (cis-UCA) and Cu(II) ions are physiological constituents of the human body and they co-occur (e.g., in the skin and the plasma). While GHK is known as Cu(II)-binding molecule, we found that urocanic acid also coordinates Cu(II) ions. Furthermore, both ligands create ternary Cu(II) complex being probably physiologically functional species. Regarding the natural concentrations of the studied molecules in some human tissues, together with the affinities reported here, we conclude that the ternary complex [GHK][Cu(II)][cis-urocanic acid] may be partly responsible for biological effects of GHK and urocanic acid described in the literature.
Therapeutic peptides in gerontology: mechanisms and applications for healthy aging.
Peptide therapeutics represent an emerging frontier in gerontological medicine, targeting fundamental hallmarks of aging including metabolic dysfunction, telomere attrition, tissue repair impairment, and hormonal decline. To comprehensively review the mechanisms, clinical applications, evidence base, and safety profiles of therapeutic peptides with demonstrated or potential applications in healthy aging and age-related conditions. A comprehensive narrative review was conducted through systematic searches of PubMed, Scopus, and regulatory databases (FDA, WADA) from inception through January 2026. Search terms included "peptide therapeutics," "aging," "gerontology," "healthspan," combined with specific peptide names (tirzepatide, epitalon, GHK-Cu, BPC-157, TB-500, Semax, CJC-1295, ipamorelin, bremelanotide). Peer-reviewed articles, clinical trials, regulatory documents, and preclinical studies were evaluated. A total of 20 primary sources were selected based on relevance, methodological quality, and contribution to understanding peptide mechanisms and clinical outcomes in aging populations. Nine peptides were identified spanning diverse aging interventions: metabolic restoration (tirzepatide), telomere biology (epitalon), dermal regeneration (GHK-Cu), tissue repair (BPC-157, TB-500), neuroprotection (Semax), growth hormone modulation (CJC-1295, ipamorelin), and sexual function (bremelanotide). FDA-approved agents demonstrated robust safety profiles from large-scale trials. Non-approved peptides showed promising preclinical and limited clinical evidence but lack long-term safety data and systematic validation. Significant knowledge gaps include optimal dosing regimens, combination therapy effects, and biomarkers for monitoring efficacy. Therapeutic peptides offer mechanistically diverse approaches to multiple aging hallmarks. While FDA-approved agents demonstrate clinical potential, investigational peptides require rigorous validation through well-designed clinical trials to establish safety and efficacy for healthspan extension.
Coassemble dopamine and GHK tripeptide into fluorescent nanoparticles for pH sensing.
Fluorescent nanostructures have been widely applied to biomedical researches and clinical diagnosis such as biolabeling/imaging/sensing and have even acted as therapy reagents. Peptide-based fluorescent nanostructures attract recent interest from biomedical researchers. Inspired by the natural existence of GHK-Cu complex with a growth factor-like effect in human blood, here we have developed a novel approach for designing nanosensors through the co-assembling of two kinds of biomolecules. By making best use of both π-π stacking between carbon rings and the easy-oxidation property of an important transmitter molecule, dopamine (DA), we successfully built up a supersensitive and robust fluorescent pH nanosensor by co-assembling oxidized DA (DAox ) with a tripeptide GHK. The GHK-DAox nanostructures have a quantum yield of 20.82%, which might be the brightest one among all the current co-assembling structures merely through unmodified biomolecules. We envision this approach could open a new avenue for not only hybrid nanostructure construction, but also may inspire the bioengineering of in vivo luminescent probes.
The tri-peptide GHK-Cu complex ameliorates lipopolysaccharide-induced acute lung injury in mice.
The tripeptide-copper complex glycyl-l-histidyl-l-lysine-Cu (II) (GHK-Cu) is involved in wound healing and tissue remodeling. Although GHK-Cu exhibits anti-aging and tissue renewing properties, its roles in acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) are still unknown. Therefore, we examined the effects of GHK-Cu in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages in vitro and ALI in mice in vivo. GHK-Cu treatment reduced reactive oxygen species (ROS) production, increased superoxide dismutase (SOD) activity while decreased TNF-α and IL-6 production through the suppression of NF-κB p65 and p38 MAPK signaling in vitro and in vivo model of ALI. Moreover, GHK-Cu attenuated LPS-induced lung histological alterations, suppressed the infiltration of inflammatory cells into the lung parenchyma in LPS-induced ALI in mice. Taken together, these findings demonstrate that GHK-Cu possesses a protective effect in LPS-induced ALI by inhibiting excessive inflammatory responses; accordingly it may represent a novel therapeutic approach for ALI/ARDS.
The Laccase-like Property of GHK-Cu and Its Applications in Colorimetric Sensing of Phenolic Compounds.
Laccase plays an important role in the detection and degradation of phenolic compounds, but it is limited by its cost and stability. In this study, the laccase-like property of copper peptide (GHK-Cu) has been revealed. In terms of enzymatic reaction kinetics, GHK-Cu has a Vmax of 1.735 × 10-4 mM·s-1 and a Km of 0.061 mM, demonstrating good substrate affinity and excellent catalytic efficiency. Then, a colorimetry was developed for rapid detection of epinephrine (EP) and 2-aminophenol (2-AP). The linear response range of EP is 20-240 μM, with a limit of detection (LOD) of 9.5 μM. The linear response ranges of 2-AP are 14-100 μM (in ultrapure water) and 2-120 μM (in seawater), with LODs of 2.56 μM and 1.65 μM. In addition, combined with a smartphone platform, a cotton-based sensor has been developed for the detection of 2-AP in seawater. The linear response ranges are 0-0.2 mM and 0.2-1 mM, with LOD of 0.033 mM. The structure of GHK-Cu provides a reference for the development of novel laccase mimetic enzymes. The constructed colorimetry offers an option for the rapid detection of phenolic compounds, and the developed cotton-based sensor enabled rapid and portable detection of 2-AP.
In Vitro and in Vivo Studies of pH-Sensitive GHK-Cu-Incorporated Polyaspartic and Polyacrylic Acid Superabsorbent Polymer.
The main aim of this study was to evaluate the in vitro and in vivo efficiency of the polyaspartic acid- and acrylic acid-based superabsorbent polymer. The synthesized polymer was first investigated to check the blood compatibility by protein adsorption and blood clotting tests. Further, the GHK-Cu peptide was incorporated within the polymer and release studies were performed to evaluate the drug-delivery efficiency of the superabsorbent polymer. The polymer with best peptide release results were further used for in vivo analysis for wound healing. The healing efficiency of polymer with and without peptide was analyzed using wound closure, biochemical assay, histopathological, and toxicity studies.
Improved laccase production by Trametes versicolor using Copper-Glycyl-L-Histidyl-L-Lysine as a novel and high-efficient inducer.
A highly efficient strategy using Copper-Glycyl-L-Histidyl-L-Lysine (GHK-Cu) as a novel inducer was developed to enhance laccase production by Trametes versicolor. After medium optimization, laccase activity increased by 12.77-fold compared to that without GHK-Cu. The laccase production of 1113.8 U L-1 was obtained by scaling-up culture in 5-L stirring tank. The laccase production induced by CuSO4 was poorer than that of GHK-Cu at the same mole concentration. GHK-Cu could increase the permeability of cell membrane with less damage, and it facilitated the adsorption, accumulation, and utilization of copper by fungal cells, which was beneficial for laccase synthesis. GHK-Cu induced better expression of laccase related genes than that of CuSO4, resulting in higher laccase production. This study provided a useful method for induced production of laccase by applying GHK chelated metal ion as a non-toxic inducer, which reduced the safety risk of laccase broth and provided the potential application of crude laccase in food industry. In addition, GHK can be used as the carrier of different metal ions to enhance the production of other metalloenzymes.
Expression and Purification of Recombinant GHK Tripeptides Are Able to Protect against Acute Cardiotoxicity from Exposure to Waterborne-Copper in Zebrafish.
In this study, an alternative method is developed to replace chemical synthesis to produce glycyl-histidyl-lysine (GHK) tripeptides with a bacterial fermentation system. The target GHK tripeptides are cloned into expression plasmids carrying histidine-glutathione-S-transferase (GST) double tags and TEV (tobacco etch virus) cleavage sites at the N-terminus. After overexpression in Escherichia coli (E. coli) BL21 cells, the recombinant proteins are purified and recovered by high-pressure liquid chromatography (HPLC). UV-vis absorption spectroscopy was used to investigate the chemical and biological properties of the recombinant GHK tripeptides. The results demonstrated that one recombinant GHK tripeptide can bind one copper ion to form a GHK-Cu complex with high affinity, and the recombinant GHK peptide to copper ion ratio is 1:1. X-ray absorption near-edge spectroscopy (XANES) of the copper ions indicated that the oxidation state of copper in the recombinant GHK-Cu complexes here was Cu(II). All of the optical spectrum evidence suggests that the recombinant GHK tripeptide appears to possess the same biophysical and biochemical features as the GHK tripeptide isolated from human plasma. Due to the high binding affinity of GHK tripeptides to copper ions, we used zebrafish as an in vivo model to elucidate whether recombinant GHK tripeptides possess detoxification potential against the cardiotoxicity raised by waterborne Cu(II) exposure. Here, exposure to Cu(II) induced bradycardia and heartbeat irregularity in zebrafish larvae; however, the administration of GHK tripeptides could rescue those experiencing cardiotoxicity, even at the lowest concentration of 1 nM, where the GHK-Cu complex minimized CuSO4-induced cardiotoxicity effects at a GHK:Cu ratio of 1:10. On the other hand, copper and the combination with the GHK tripeptide did not significantly alter other cardiovascular parameters, including stroke volume, ejection fraction, and fractional shortening. Meanwhile, the heart rate and cardiac output were boosted after exposure with 1 nM of GHK peptides. In this study, recombinant GHK tripeptide expression was performed, along with purification and chemical property characterization, which revealed a potent cardiotoxicity protection function in vivo with zebrafish for the first time.
Quick links (PubMed)
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