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Research peptide — not a dietary supplement
GHK-Cu is a research compound, not a regulated dietary supplement. It is typically administered by injection and sold “for research use only.” The evidence below is largely preclinical (animal and in-vitro) or early-stage, so no evidence score is assigned. This page is provided for transparency and education — it is not a recommendation to use. Consult a qualified healthcare provider, and be aware that purity, dosing, and legal status vary by jurisdiction.
What the evidence says
Most GHK-Cu studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from mixed-quality randomised trials published 2000–2018 with a typical study size of 13 participants.
Based on 11 studies · 1 RCT · 13 total participants
Confidence
LowBy outcome
GHK-Cu has an evidence score of 3/10 — emerging evidence based on 11 indexed studies. A naturally occurring copper-binding tripeptide used in topical skincare for collagen support and skin repair. Honest appraisal: the believable human evidence is TOPICAL/cosmetic — and even there it's thin and mostly formulation-level (e.g. one small RCT after laser resurfacing where patients felt their skin was better but objective measures didn't differ). Most mechanistic claims come from in-vitro and animal work. The injectable use sold on the grey market has no human safety or efficacy data and is research-use-only. Representative study: PMID 16847171.
The commonly studied dose of GHK-Cu is Topical cosmetic use only: leave-on serums/creams typically 1-2% GHK-Cu (≈0.05-0.2% in some formulas), applied once or twice daily. No validated systemic dose exists.. Individual needs vary — start at the lower end of the range and adjust based on how you respond.
Semaglutide
Mostly mechanism / observationalAn FDA-approved GLP-1 receptor agonist (Ozempic/Rybelsus for type 2 diabetes, Wegovy for chronic weight management) with genuinely strong, large-RCT evidence for glycemic control and substantial weight loss, plus a cardiovascular-outcomes benefit. Honest appraisal: this is a real prescription medicine with real efficacy AND real risks — a boxed warning for thyroid C-cell tumors, pancreatitis and gallbladder risk, very common GI side effects, and growing concern about grey-market/compounded versions. It is included here for reference only, not as a supplement and not auto-recommended.
Last reviewed June 2026 · evidence from 11 studies · how we score
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
Copper Tripeptide-1 (Glycyl-L-Histidyl-L-Lysine:Copper)
A naturally occurring copper-binding tripeptide used in topical skincare for collagen support and skin repair. Honest appraisal: the believable human evidence is TOPICAL/cosmetic — and even there it's thin and mostly formulation-level (e.g. one small RCT after laser resurfacing where patients felt their skin was better but objective measures didn't differ). Most mechanistic claims come from in-vitro and animal work. The injectable use sold on the grey market has no human safety or efficacy data and is research-use-only.
The only controlled human study is a tiny post-laser RCT (n=13) showing improved patient satisfaction but no objective skin change; nearly all other support is in-vitro and animal mechanism, with no data for injectable use.
GHK-Cu (glycyl-L-histidyl-L-lysine bound to copper(II), 'copper tripeptide-1') is a small endogenous peptide found in human plasma that binds copper with high affinity. It is a long-standing cosmetic ingredient: topically it is used in serums and creams marketed for skin firmness, fine lines, and post-procedure repair.
The honest evidence split matters here. (1) TOPICAL/cosmetic: there is real but limited human data.
The best-controlled human study is a small randomized trial in patients after CO2 laser resurfacing — a GHK-Cu skincare regimen produced significantly higher patient-rated skin-quality satisfaction, but blinded objective assessment found no significant difference in erythema, wrinkles, or skin quality versus the control regimen.
Other human reports use multi-ingredient cosmetic formulations, so the GHK-Cu-specific contribution is hard to isolate.
(2) MECHANISM: a substantial body of in-vitro and animal work shows GHK-Cu stimulates collagen, decorin, and glycosaminoglycan synthesis, modulates matrix metalloproteinase (MMP-2/TIMP) expression in dermal fibroblasts, supports keratinocyte/stem-cell proliferation, and — in gene-expression (Connectivity Map) analyses — shifts disease-associated transcriptional patterns toward tissue-repair programs.
Animal models report improved wound/scald healing and antifibrotic effects. These are mechanistically interesting but are preclinical. (3) INJECTABLE: GHK-Cu is increasingly sold for subcutaneous or intramuscular injection for 'anti-aging' and systemic repair.
There are NO human trials of injectable GHK-Cu, no human safety data, and copper-loading carries real toxicity concerns; this use is unapproved, research-use-only, and additionally exposed to grey-market sourcing/purity risk.
Overall: defensible low/emerging evidence for the evidenced topical cosmetic use; essentially unsupported for injectable use.
GHK chelates copper(II) with an affinity similar to the copper-transport site on albumin, forming GHK-Cu — proposed to deliver copper to skin cells and influence copper-dependent enzymes.
In fibroblast cultures and animal wounds GHK-Cu stimulates type I collagen, decorin, and glycosaminoglycan production, and modulates MMP-2 / TIMP expression involved in matrix remodeling.
Connectivity-Map and microarray analyses report GHK can shift disease-associated gene-expression signatures (e.g. emphysema, nervous-system aging) toward tissue-repair patterns — preclinical/computational evidence.
In-vitro and animal work reports radical-scavenging, carbonyl-quenching, and anti-inflammatory effects; not demonstrated as clinical outcomes in humans.
How GHK-Cu works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
Tap node to isolate • Pinch to zoom • Tap edge for research
Topical cosmetic use only: leave-on serums/creams typically 1-2% GHK-Cu (≈0.05-0.2% in some formulas), applied once or twice daily. No validated systemic dose exists.
Can be taken without food
| Form | Type |
|---|---|
| 🧴Topical serum/cream (copper tripeptide-1) | Recommended |
| 🧴Copper-free GHK topical | Alternative |
Copper-free GHK shows broadly similar in-vitro effects in some studies, but the cosmetic literature is largely on the copper complex. Injectable forms are not a recommended alternative.
Minimum: 4 weeks
Optimal: 12 weeks
Cycling: Not required
Note: Topical application to clean skin, once or twice daily. Not an oral supplement; injectable use is not supported by human data.
Dose-response data unavailable. The current published research for GHK-Cu does not provide sufficient dose-specific outcome data to generate reliable dose-response curves.
Refer to the Dosage & Timing section above for recommended dose ranges based on available evidence.
Used topically for firmness and fine lines; the best human RCT found improved patient-rated satisfaction but no objective difference vs control after laser resurfacing.
Collagen/decorin synthesis and faster wound or scald healing are shown mainly in fibroblast cultures and animal models, not in controlled human wound trials.
No human trials, no human safety data, and copper-toxicity concerns. Grey-market injectable use is research-use-only.
Avoid — no human trials, no safety data, copper-toxicity and grey-market purity risk. Research-use-only.
Avoid copper-delivering products entirely.
Not studied — avoid beyond ordinary cosmetic topical use, and avoid injectable use entirely.
Patch test topical products and introduce slowly.
Layering with strong actives (retinoids, AHAs/BHAs, vitamin C) may increase irritation for some users; theoretical and product-dependent, not a systemic interaction.
GHK-Cu delivers copper; in anyone managing copper balance (e.g. Wilson's disease therapy), copper-containing products should be avoided. Most relevant to injectable/systemic exposure.
Tip: Patch test; reduce frequency or concentration; avoid layering with other irritants
Tip: Discontinue if rash or itching develops
Tip: Do not inject; no human safety data and copper-loading carries real toxicity risk
Timing is flexible for GHK-Cu — consistent daily use matters more than the time of day. Topical cosmetic peptide applied to clean skin once or twice daily; not ingested.
GHK-Cu should be used with caution — talk to a healthcare provider before taking it. The most commonly reported side effects are local skin irritation / redness (topical), contact sensitivity / allergic reaction (topical), unknown systemic effects (injectable). Use caution if any of these apply to you: Injectable/systemic use (no human safety data; copper-toxicity risk); Wilson's disease or other copper-overload disorders (avoid copper-delivering products); Pregnancy/breastfeeding (not studied).
Tirzepatide
Mostly mechanism / observationalAn FDA-approved prescription medication (Mounjaro for type 2 diabetes, Zepbound for obesity and obstructive sleep apnea), not a dietary supplement. Honest appraisal: in head-to-head phase-3 trials it is the most effective approved weight-loss drug to date — up to ~21% body-weight loss over 72 weeks and superior to semaglutide — but it is a real medicine with real risks: a boxed warning for thyroid C-cell tumors, common GI side effects, and pancreatitis/gallbladder signals. Do not source or use it outside a prescription.