Cosmetic & skin

AHK-Cu

Also called L-alanyl-L-histidyl-L-lysine-Cu(II), Ala-His-Lys-Cu, Tripeptide-copper complex (AHK)

AHK-Cu is a tiny three-amino-acid peptide (alanine, histidine, lysine) bound to copper. It is a close cousin of the better-known GHK-Cu and is mostly found in hair-growth serums and skin-care products. The main evidence is a single 2007 lab study on human hair follicles grown in a dish; no human trials have been published.

Preclinical onlyStudied in cells or animals only. Effects in people are unknown.

All printable flashcards

Drawn from its published sequence: 3 residues, one bead each.

Overview

How it works

Proposed, based on lab work only. In a 2007 study, AHK-Cu at very low concentrations made isolated human hair follicles grow longer and increased the growth of dermal papilla cells, the signaling cells at the base of a hair follicle ¹. It also shifted survival-related proteins in those cells (higher Bcl-2/Bax ratio, less cleaved caspase-3 and PARP), suggesting it may slow programmed cell death, although the drop in the count of dying cells was not statistically significant ¹. The same paper cites earlier work that the tripeptide-copper complex raises fibroblast growth and VEGF production ¹. None of this has been confirmed in people.

What research shows

Pyo et al. 2007 (cell and organ-culture study): AHK-Cu at 10^-12 to 10^-9 M lengthened human hair follicles grown ex vivo and increased dermal papilla cell proliferation ¹.
Same study: at 10^-9 M, AHK-Cu raised the Bcl-2/Bax ratio and lowered cleaved caspase-3 and PARP in dermal papilla cells; the reduction in apoptotic cells measured by flow cytometry was not statistically significant ¹.
No published randomized or controlled human trials of AHK-Cu for hair or skin were found in this review.

Doses studied in people

No published human dosing data exist; AHK-Cu is used as a topical cosmetic ingredient and the only key study used concentrations in a lab dish.

Read this first: these are the amounts given to participants in published studies or written on official prescribing labels, reported for reference. They are not recommendations. Trial doses were chosen for specific patients under medical supervision, and a dose that is safe in one person can be harmful in another.

Vial math

Many research vials hold 5 or 10 mg of powder. This table shows how much ends up in each mark on a U-100 insulin syringe for common amounts of added liquid. It is arithmetic only, not a dose.

Vial	Liquid added	Concentration	Per unit (0.01 mL)
5 mg	1 mL	5 mg/mL	50 mcg	Open in calculator
5 mg	2 mL	2.5 mg/mL	25 mcg	Open in calculator
5 mg	3 mL	1.67 mg/mL	16.7 mcg	Open in calculator
10 mg	1 mL	10 mg/mL	100 mcg	Open in calculator
10 mg	2 mL	5 mg/mL	50 mcg	Open in calculator
10 mg	3 mL	3.33 mg/mL	33.3 mcg	Open in calculator

More sizes: all vial sizes · How this works: Syringes and units · Reconstitution guide.

Safety

No published human safety studies of AHK-Cu were found; long-term safety is unknown.
Evidence of effect comes from lab-dish experiments only, so benefits claimed on product labels are not proven in people ¹.
Injectable 'research' versions sold online have no human safety data and may vary in purity.

Report side effects of any drug or product to the FDA through MedWatch. For a possible poisoning in the US, call Poison Control at 1-800-222-1222.

Legal status

FDA: Not FDA-approved. Sold as a cosmetic ingredient; under FDA rules, a product claiming to regrow hair or change body structure or function is treated as a drug, not a cosmetic ⁴.
Compounding: Not named on FDA's 503A Category 2 (significant safety risks) page or among withdrawn nominations (page current as of 04/22/2026), and not found on FDA's 503A nominations list as retrieved ²³.
Sports (WADA): Not named on the 2026 Prohibited List ⁵. As a cosmetic ingredient it is unlikely to be relevant to sport, but any unapproved injectable form could fall under S0 (non-approved substances); athletes should confirm with their anti-doping organization.
Other: No drug approval found in any country.

Rules change often. See Legal status of peptides for how these categories work.

History

AHK-Cu was studied as a hair-growth agent by a Korean research group (Pyo, Kim and colleagues at Seoul National University), who published the main in-vitro paper in Archives of Pharmacal Research in 2007 ¹. It later appeared in cosmetic hair and scalp products, usually marketed alongside GHK-Cu as a 'copper peptide.'

Common questions

Does AHK-Cu regrow hair?

It has not been shown to in people. A 2007 lab study found it lengthened human hair follicles and boosted dermal papilla cell growth in a dish, but no human trials have been published ¹.

How is AHK-Cu different from GHK-Cu?

Both are three-amino-acid peptides bound to copper; AHK-Cu has alanine where GHK-Cu has glycine ¹. GHK-Cu occurs naturally in the body and has more research, including small human skin studies.

Is AHK-Cu FDA-approved?

No. It is sold as a cosmetic ingredient, and FDA treats products that claim to regrow hair as drugs, which would need approval ⁴.

Is AHK-Cu banned in sport?

It is not named on the 2026 WADA Prohibited List; unapproved substances can still fall under the S0 catch-all, so athletes should check with their anti-doping body ⁵.

Related compounds

Longevity & mitochondrialEarly human dataFlashcard

GHK-Cu

Copper tripeptide-1 · Copper peptide

GHK-Cu is a tiny three-amino-acid peptide (GHK) bound to copper.

Sources

Last reviewed 2026-10-26 · How we research · Found an error? See our corrections policy.