Carl read the papersWhat it actually is
AHK-Cu is the tripeptide alanine-histidine-lysine bound to copper. It sits alongside GHK-Cu in the copper peptide family, sharing the same basic idea: a short peptide that carries copper into tissue, where copper acts as a cofactor in a range of repair enzymes.
Where GHK-Cu's research is largely about skin — collagen, wound healing, remodelling — AHK-Cu's is pointed at hair follicles. The patent literature on peptide copper complexes for hair growth is the most substantial part of its file.
How it’s thought to work
- Copper delivery — Carries copper into tissue, where it acts as a cofactor for lysyl oxidase and other repair enzymes.
- Follicle stimulation — The patent work centres on stimulating the dermal papilla and prolonging the anagen growth phase.
- Angiogenesis — Copper peptides promote local blood vessel formation — the mechanism proposed for improved follicle perfusion.
- VEGF signalling — Reported to increase VEGF expression around the follicle, though most of this work is in vitro.
What the research says
Modest and largely preclinical. There is a real patent literature on peptide copper complexes for stimulating hair growth, and in vitro work on tripeptide-copper effects on human hair follicles. Animal work found that AHK-Cu injection produced hair retention in roughly a 0.25 cm radius around the injection site, most clearly in the 0.1–0.5 mg dose range — a very local effect. Human clinical dose-finding has not been done.
- Patent literature on peptide copper complexes for hair growth is the substantial part of the file.
- In vitro work on tripeptide-copper effects in human hair follicles.
- Animal injection data showed hair retention in a ~0.25 cm radius around the site — a local, not systemic, effect.
- No established human dosing protocol exists.
Watch: AHK-Cu explained
Video by Kevin Li on YouTube. Not affiliated with Peptide Carl and not an endorsement — included because a second explanation of the same mechanism is often what makes it click.
Reported protocols
These are the doses the peptide community actually reports running (Reddit & forums), alongside published research — logged for education, not as a recommendation to use.
| Parameter | Commonly reported range |
|---|---|
| Topical serum | The common form — roughly 1–2 mg/mL, about 0.1–0.2%, applied to the scalp |
| Frequency | Once or twice daily is the most commonly reported cadence |
| Reconstitution for topical use | A 20 mg vial into 10–20 mL of carrier gives roughly the 1–2 mg/mL range |
| Injection | Animal work used 0.1–0.5 mg locally; the effect was confined to a small radius around each site |
| Timeline | Hair responds on follicle cycle time — 3–6 months before anything is assessable |
| Community tip | The consistent point is that this is a topical compound. The vial format invites injection, but the animal data showed the effect was local to a quarter-centimetre around each site — which for a whole scalp is not a practical protocol. |
Common use cases
| Goal | Community protocol notes |
|---|---|
| Scalp / hair support | 1–2 mg/mL topical serum, once or twice daily, assessed at 3–6 months |
| Alongside GHK-Cu | the family pairing — follicles and skin respectively |
| Why not injection | the animal effect was confined to ~0.25 cm around each site |
Mixing it (reconstitution)
Freeze-dried peptides must be reconstituted with bacteriostatic water before they can be measured. Carl’s calculator turns “mg in the vial + ml of water + target dose” into “units on the syringe” — and tells you how long the vial lasts.
→ Open the Reconstitution Calculator
Injection & handling
In practice this is a topical compound rather than an injected one. The usual approach is to reconstitute into a carrier at roughly 1–2 mg/mL — a 20 mg vial into 10–20 mL — and apply to the scalp once or twice daily. The animal injection data is the reason topical wins: hair retention appeared only within about a quarter of a centimetre of each injection site, so covering a scalp by injection is not realistic. Keep copper peptides away from direct-acid vitamin C in a routine, and expect to wait three to six months before there is anything to assess.
Stacks it appears in
- With GHK-Cu — The obvious pairing — the same family, with GHK-Cu's research pointed at skin and AHK-Cu's at follicles.
- With minoxidil — Frequently described together in scalp routines. Different mechanisms, no interaction data.
