GHK-Cu has been tested in people, mostly in wound trials; AHK-Cu has only been tested on hair follicles in a lab dish. Neither is an FDA-approved drug as of October 2026.
For hair, neither copper peptide has been tested on its own on a human scalp. AHK‑Cu's case is one 2007 study in which human scalp follicles grew longer in a lab dish. The closest human hair data for GHK is a 45‑patient placebo‑controlled trial of GHK without copper, bound to 5‑aminolevulinic acid, in which one of two strengths raised hair counts more than placebo. For skin and wounds, GHK‑Cu has the only human trials of the two, and its two phase 3 wound trials did not beat placebo.
Every claim on this page is labeled by what was tested: in people, in animals or cells, or a regulatory fact. How we grade evidence: editorial policy.
| Item | GHK‑Cu | AHK‑Cu |
|---|---|---|
| What it is | Glycine, histidine and lysine holding a copper ion; found naturally in human blood | Alanine, histidine and lysine holding a copper ion; the same three sit inside human albumin |
| Tested in people for | Diabetic and leg ulcers, skin after laser resurfacing | Nothing yet |
| Evidence label | Tested in people (wound trials, mostly negative); hair tested in people only as GHK without copper | Tested in animals or cells only: one study on human follicles in a dish |
| FDA status | Not an approved drug; non-injectable GHK-Cu under FDA compounding review | Not an approved drug; on none of FDA's compounding lists |
| WADA 2026 | Not named; falls under S0, non-approved substances, banned at all times | Not named; falls under S0, non-approved substances, banned at all times |
| Last checked | October 16, 2026 | October 16, 2026 |
New trials, FDA changes and side-effect reports, written in plain English. Every result says whether it was tested in people or in animals.
Each row names its evidence type. Every study named here is linked in the sources list at the bottom of the page.
| GHK-Cu | AHK-Cu | Evidence type | |
|---|---|---|---|
| Largest human study | 511 patients with diabetic foot ulcers in two phase 3 trials of a GHK-Cu gel, results announced by the company in 1994 | None. No published study has given AHK-Cu to a person | Tested in people |
| Placebo-controlled result in people | The phase 3 gel was no better than placebo, and a copper tripeptide cream showed no difference from placebo in 86 leg ulcer patients (Bishop, 1992) | No placebo-controlled trial exists | Tested in people |
| Hair in people | Only GHK without copper, bound to 5-ALA: in 45 patients with male pattern hair loss, the change in hair count beat placebo at one of two strengths over 6 months (Lee, 2016) | No human hair study | Tested in people |
| Hair in the lab | Rodent follicle studies from ProCyte in 1991 and 1993 used copper peptide complexes without naming GHK-Cu | Human scalp follicles grew longer in a dish and dermal papilla cells multiplied faster (Pyo, 2007) | Tested in animals or cells |
| Skin and wounds in the lab | Raised collagen in human fibroblast cultures (Maquart, 1988) and in rat wound chambers (Maquart, 1993) | Not studied; the only AHK-Cu paper in PubMed is the 2007 hair follicle study | Tested in animals or cells |
| Where it comes from | Isolated from human serum in 1973 and identified as GHK in 1977 | Its sequence matches amino acids 2 to 4 of human albumin's copper-binding tip, Asp-Ala-His-Lys | Tested in animals or cells |
| Registered trials, October 2026 | One: a GHK-Cu gel against an identical vehicle gel on skin wounds in 60 healthy adults (China, recruiting since February 2026) | None on ClinicalTrials.gov | Regulatory fact |
| US status, October 2026 | Not an approved drug. Non-injectable GHK-Cu is in FDA's Category 1 (under evaluation); injectable GHK-Cu sits in no category | Not an approved drug, and not in any of FDA's three 503A nomination categories | Regulatory fact |
One amino acid. GHK-Cu starts with glycine and AHK-Cu with alanine, and both hold a copper ion. GHK-Cu occurs naturally in human blood and has human trials; AHK-Cu has one study, on follicles in a dish.
GHK was first reported in 1973 by Loren Pickart as a factor in human serum that kept liver cells alive longer in culture, and was identified as glycyl-histidyl-lysine in 1977. In human fibroblast cultures, GHK-Cu raised collagen production starting between 1 and 10 picomolar, with the peak at 1 nanomolar (tested in animals or cells, Maquart, 1988). It also goes by copper tripeptide-1, one of the names PubChem lists for it, and that is the name in the ingredient list of the scalp serum in a 2024 dandruff study (Patel, 2024).
AHK-Cu swaps the glycine for alanine. The same Ala-His-Lys run sits at positions 2 to 4 of the copper-binding tip of human albumin, Asp-Ala-His-Lys (Bar-Or, 2001). A PubMed search for AHK-Cu returns one paper: the 2007 hair follicle study.
Nobody has compared them, and neither has been tested on its own on a human scalp. AHK-Cu has the only study on human follicles; GHK has one small placebo-controlled hair trial, run without copper and bound to another compound.
Tested in animals or cells: in a 2007 study at Seoul National University, hair follicles taken from human scalps grew longer in culture when bathed in AHK-Cu at 1 picomolar to 1 nanomolar, and dermal papilla cells, the cells at the base of each follicle that drive growth, multiplied faster. At 1 nanomolar the drop in dying papilla cells was not statistically significant, though the cells' survival proteins shifted in the protective direction (Pyo, 2007).
Tested in people: in a 6-month randomized, double-blind trial at Kyungpook National University, 45 patients with male pattern hair loss sprayed one of two strengths of ALAVAX, a complex of GHK and 5-aminolevulinic acid with no copper, or a placebo on the scalp. Hair counts rose by 52.6 and 71.5 in the two ALAVAX groups and by 9.6 on placebo, The change in hair count beat placebo by a statistically clear margin only for the weaker of the two strengths. There was no difference in hair length or thickness, and no adverse events were reported (Lee, 2016).
Tested in animals: ProCyte, the company that developed GHK-Cu, reported that copper peptide complexes stimulated hair follicles in mice in 1991 (Trachy, 1991), and a copper-binding peptide called PC1031 enlarged follicles on the backs of fuzzy rats about as much as topical minoxidil (Uno, 1993). Neither report says the peptide was GHK-Cu or AHK-Cu.
GHK-Cu has, in wound and skin trials, and the larger ones did not beat placebo. AHK-Cu has never been given to a person in a published study.
Tested in people: a multicenter, randomized, evaluator-blinded trial of a GHK-Cu gel in diabetic foot ulcers reported median ulcer closure of 98.5% against 60.8% on vehicle gel, and infections in 7% against 34% (Mulder, 1994). Then in October 1994 ProCyte announced that its phase 3 trials, 511 patients in two studies, found the gel no better than placebo, and its share price fell 68% that day (The Pharma Letter, 1994). FDA cleared the gel in 1996 as a wound dressing device, not as a drug.
Tested in people: in 86 patients with venous leg ulcers, a copper tripeptide cream showed no difference from placebo, while silver sulfadiazine cream shrank the ulcers (Bishop, 1992). In 13 patients after laser resurfacing around the mouth, blinded evaluators and imaging found no difference in redness, wrinkles or skin quality between skin care regimens with and without GHK-Cu, though patients on GHK-Cu rated their skin higher (Miller, 2006).
A 2026 systematic review in Aesthetic Surgery Journal found 20 studies of GHK-Cu used alone for aesthetic purposes, 18 of them preclinical and 2 randomized trials (Mokhtar, 2026). A trial of a GHK-Cu gel against an identical vehicle gel on standardized skin wounds in 60 healthy adults began recruiting in China in February 2026.
No published human study. ClinicalTrials.gov lists no AHK-Cu trial.
Patients. Tested in people. The 511-patient result was announced by the company and never published as a paper, and the hair trial used GHK without copper.
No study has tested the pair, in people or in a dish. Each peptide was only ever studied on its own.
The human scalp studies that included a copper peptide tested whole formulas with no copper-free comparison. A 15-day study of a dandruff scrub and a serum listing copper tripeptide-1 among five ingredients had no control group and was run with the product's manufacturer (Patel, 2024). In an uncontrolled study of 1,000 patients, an injected hair formula held six ingredients, among them growth factors, thymosin beta-4 and copper tripeptide-1 (Kapoor, 2018). Neither design can show what the copper peptide did.
Neither is an FDA-approved drug. As of October 2026, non-injectable GHK-Cu is under FDA evaluation for pharmacy compounding, injectable GHK-Cu is in no category, and AHK-Cu is on none of FDA's compounding lists.
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