GHK-Cu is two products under one name: a cosmetic ingredient with a handful of small human trials, and an injectable research peptide with none. The dose question splits the same way. This page reports the topical concentrations the trials and products state, then the injectable figures the clinic and vendor pages state, and it keeps the two apart, because evidence for a serum is not evidence for a syringe. It does not recommend anything. How brands appear on this site is set out on our disclosure page.
What it is, and its status
GHK-Cu is the tripeptide glycine-histidine-lysine bound to a copper ion, present in human plasma and declining with age. As a cosmetic ingredient (INCI copper tripeptide-1) the Cosmetic Ingredient Review Expert Panel concluded in June 2014 that it is safe as used, noting typical use concentrations under 10 ppm at that time. As an injectable it has no approval; FDA's bulk-substances page, updated 2026-04-22, records GHK-Cu among peptides reviewed for immunogenicity and peptide-impurity concerns with limited human safety data (FDA). It is not named on the 2026 WADA Prohibited List; S0 covers non-approved substances generally. The 2026 Sports Medicine review lists it among gray-market compounds "with thin human safety data" (Mendias and Awan).
Topical: what the trials and products state
| Source | What it states | Kind of source |
|---|---|---|
| Badenhorst et al. 2016, randomized double-blind, 40 women aged 40–65, 8 weeks | Wrinkle volume down 24.1% with a GHK-Cu nano-carrier serum vs 15.0% with the vehicle; the paper does not state the GHK-Cu percentage; funded by the serum's maker | Trial |
| 2002 conference abstracts (71 and 41 women, 12 weeks) and a 1998 20-subject thigh biopsy study | Reduced signs of photoaging; more procollagen on biopsy; no concentration reported in the reviews | Small studies, mostly unpublished in full |
| Cosmetic Ingredient Review, June 2014 | Copper tripeptide-1 "safe in the present practices of use and concentration in cosmetics"; "typical use concentrations of these ingredients are < 10 ppm" | Industry-funded safety panel |
| The Ordinary Multi-Peptide + Copper Peptides 1% | 1% copper tripeptide-1, $32 for 30 mL | Product page |
| NIOD CAIS3 | 1% GHK-Cu plus 1% GHK, $62 for 15 mL | Product page |
Ten ppm is 0.001%; a 1% serum is a thousand times that, so current products sit far above the use data the safety review surveyed, and the one trial paper that could be opened does not say what it used. Peptide Glow Journal's copper-peptide page has the trials in full.
Injectable: what the pages state, and what the literature does not
A PubMed search on 2026-09-05 for GHK-Cu with injection, subcutaneous or intravenous terms in humans returned two records: a biomaterials paper on GHK-Cu-grafted microspheres for bone engineering and a narrative review. There is no human study of injectable GHK-Cu at any dose.
| Source | What it states | Kind of source | Date opened and link |
|---|---|---|---|
| Peptide Dosing Protocols | "Community discussions and protocol-style references commonly describe 1–2 mg per day SubQ for a 4–8 week cycle"; conservative 1.0 mg five days on, two off, 4 weeks; standard 1.0–1.5 mg daily, 4–6 weeks; higher 1.5–2.0 mg daily, 6–8 weeks; "50 mg vial reconstituted with 2.0 mL bacteriostatic water (25 mg/mL), with one daily injection at 1 mg (0.04 mL = 4 units on a U-100 syringe)"; topical "1% to 3% by weight" | Protocol site | Reviewed August 2026 |
| FormBlends | Injectable "1 to 2 mg (1,000 to 2,000 mcg)" per dose, "3 to 7 times per week"; 50 mg vial with "5 mL bacteriostatic water = 10 mg/mL"; cycles "8 to 12 weeks on, 4 weeks off" or continuous per the prescriber; topical "2 to 5% (compounded creams or serums)" once or twice daily | Vendor-affiliated guide | Updated 2026-06-02 |
| Clinic and vendor pages returned by a 2026-09-05 search (Perfect B, PS Peptides, PeptidesExplorer, Peptide Dossier) | 1–2 mg per day, "1 mg to 4 mg per day" in some; 30-day cycles split into two 15-day phases with a 30-day rest | Clinic and vendor guides, as summarized; not individually opened | Range only |
The injectable convention is narrow (1 to 2 mg daily) and universal across the pages, which again reflects copying rather than evidence: there is no trial, no pharmacokinetic study and no safety study of GHK-Cu given subcutaneously to a person. The topical percentages the same pages quote (1 to 5%) are for a different route with its own small trials.
Reconstitution arithmetic as the guides state it
GHK-Cu is sold in larger vials than most peptides because the quantities on the pages are in milligrams. A 50 mg vial with 2 mL of bacteriostatic water is 25 mg/mL (25,000 mcg/mL, 250 mcg per U-100 unit): 1 mg is 4 units, 2 mg is 8. The same vial with 5 mL is 10 mg/mL (100 mcg per unit): 1 mg is 10 units, 2 mg is 20. Our reconstitution page has the procedure as an FDA label describes it and the arithmetic for any combination.
What is not known
Whether injected GHK-Cu does anything in a human, at any dose, by any schedule; what its safety is by injection; and what concentration the topical trials used, since the papers do not say. The topical evidence is small and industry-linked; the injectable evidence is absent. Nothing on this page is a recommendation.
Sources and dates
Opened 2026-09-05: PubMed search for injectable GHK-Cu in humans (2 records, neither a trial); Peptide Dosing Protocols GHK-Cu page (August 2026); FormBlends GHK-Cu protocols (2026-06-02); Mendias and Awan, Sports Medicine 2026 (PMID 41966639); FDA's bulk-substances page (2026-04-22); the 2026 WADA Prohibited List; the topical trial and product figures as documented on Peptide Glow Journal's copper-peptide page (Badenhorst 2016, CIR 2014, The Ordinary and NIOD product pages). Corrections go to the contact page.