AHK-Cu
Skin Health, Hair Growth
In short
- A copper-binding tripeptide (Ala-His-Lys), related to but distinct from GHK-Cu.
- Used almost exclusively in topical cosmetic formulations, particularly for hair.
- The evidence base is considerably thinner than GHK-Cu's, which is itself mostly cosmetic-grade.
- The same copper consideration applies to any systemic use, and there is even less reason to inject this one.
- A cosmetic ingredient rather than a research compound.
Structure
How it works
AHK is a tripeptide that, like GHK, chelates copper(II). The copper complex is the active form.
Proposed mechanisms mirror GHK-Cu: stimulation of dermal fibroblast activity, collagen synthesis, and angiogenesis. For hair applications the claimed effect is on follicular blood supply and on prolonging the anagen growth phase.
Copper is a required cofactor for lysyl oxidase, which cross-links collagen and elastin, giving a plausible route to the dermal effects.
What the research shows
Cosmetic studies, largely manufacturer-generated, report effects on hair growth parameters and skin quality.
Independent controlled trials are scarce, and the evidence is weaker than for GHK-Cu, which is already limited to cosmetic-grade endpoints.
No therapeutic claims are supported.
Dosing in the literature
Figures below are quoted from published studies, with the species or population they were measured in. They are records of what was studied, not recommendations.
| Studied in | Amount | Route | Source |
|---|---|---|---|
| Cosmetic formulation studies | Typically low concentrations in topical serums; see source | topical | PubMed |
Commonly reported ranges
These are amounts people report using. They are not from any study, have not been evaluated for safety, and are reproduced here only because they circulate widely and are better seen alongside the evidence than instead of it.
| Reported by | Amount | Route |
|---|---|---|
| Commonly reported for topical hair use | Applied as part of a topical serum | topical |
A topical cosmetic ingredient with formulation concentrations rather than doses. Injection is not an established use and carries the copper-load consideration without any supporting rationale.
Handling and storage
Applied topically in a serum, usually to the scalp for hair applications or to skin.
As with GHK-Cu, the solution is characteristically blue from the copper complex.
Side effects
Topical use is generally well tolerated, with irritation and contact sensitivity the main issues.
Systemic use raises the same copper consideration as GHK-Cu: copper has a narrow safe range, and chronic excess causes hepatic and neurological toxicity. Wilson disease or any disorder of copper handling is a clear reason to avoid systemic exposure.
There is no evidence base at all for injecting this peptide.
Combinations
In topical formulations it is commonly combined with GHK-Cu and other cosmetic peptides.
The skincare convention of separating copper peptides from direct vitamin C and strong acids in the same application applies here as it does to GHK-Cu.
Research status
Minimal. The cosmetic peptide literature is dominated by manufacturer studies with small samples and subjective endpoints, and AHK-Cu has less than GHK-Cu.
Legal status
Permitted as a cosmetic ingredient. Not approved as a drug for any indication anywhere.
WADA status
Not on the WADA Prohibited List. A topical cosmetic ingredient with no relevance to sport.
Conclusion
AHK-Cu is GHK-Cu's less-studied relative, used mainly in hair products. The topical use is low-risk and modestly evidenced at best.
If you are considering a copper peptide, GHK-Cu has the better evidence — and for either of them, topical is where the evidence lives.
Sources
Track your own AHK-Cu protocol
Peppers logs your doses, models your levels from this half-life, tracks your vials and tells you when you will run out. Free on iPhone.
Reference and educational information only. Not medical advice. Nothing here diagnoses, treats, or prescribes, and nothing here is a recommendation to use any compound. The compounds described are research chemicals and are not approved for human consumption. Legal and anti-doping status change — the review date above is when these claims were last checked. Talk to a qualified clinician about anything you intend to take.