AHK-Cu

GHK-Cu’s hair-focused cousin. One amino acid is swapped, and the target moves to the hair follicle.

Evidence: ELab & animal what's this?
Grade E. It rests on essentially one laboratory study. Systemic injection is unsupported.
Also known as: Copper Tripeptide-3 · Ala-His-Lys copper
Class: Synthetic copper-binding tripeptide (~417 Da); cosmetic ingredient

The 30-second version

WhatAlanine–histidine–lysine bound to copper. GHK-Cu has glycine where this has alanine.

Why people use itThicker hair and a healthier scalp, as a serum or by scalp mesotherapy.

The honest catchNo human trial of AHK-Cu alone, and copper peptides cross intact skin poorly.

What it is

AHK-Cu is a small synthetic copper peptide. The copper does the work, and the three amino acids carry it to the right place. It’s a topical and local agent found in hair serums and some scalp-injection protocols. It isn’t meant to be a systemic injectable, and nothing supports using it that way.

How it works

Target: dermal papilla cells, the control room at the base of each hair that sets the growth cycle.

Signal. The copper prompts papilla cells to multiply.

Blood supply. VEGF rises, feeding the follicle.

Stay in growth. TGF-β1, which pushes hair toward resting and shedding, falls.

Outcome (in culture). Longer follicles and a more active papilla.

What the research shows

In the lab: Pyo and colleagues (2007) treated cultured human hair follicles and papilla cells with picomolar-to-nanomolar AHK-Cu. Follicles lengthened, papilla cells proliferated, VEGF rose and TGF-β1 fell. A reduction in cell death didn’t reach significance¹. In people and animals: there’s no standalone trial. The impressive copper-peptide hair numbers mostly belong to GHK-Cu, to combination products, or to studies that added microneedling.

The biology works in a dish. Nobody has tested whether a serum delivers enough to a real scalp.

Evidence at a glance

Use	Grade	Best evidence	Main gap	Read
Hair growth, topical	DCommunity use	Follicle elongation in culture¹	One lab study	Plausible
Follicle blood supply	ELab & animal	VEGF up, TGF-β1 down¹	Cell level	Theory support
Systemic injection	ELab & animal	No data	—	Not supported

Dosing: what has been reported

Not a recommendation. These figures describe what was studied or what circulates in practice, kept separate so you can see how solid each one is. Speak with a qualified clinician before acting on any of it.

Setting	Figure	Route	Grade
Published human	None (culture concentrations only)	—	—
Cosmetic serum	100–500 ppm (0.01–0.1%), kept under ~0.2%, daily	Scalp	D
Scalp mesotherapy	~0.5–1 mg/mL, 1–2 mL per session, weekly to monthly	Intradermal	D
Systemic subcutaneous	Not supported	—	—

Apply to a clean scalp, since oil and product build-up block what little gets through. Microneedling is often used to open a path. Judge results only after 3–6 months.

Preparing & storing

Serums come ready-made. Powder for mesotherapy reconstitutes like other copper peptides: bacteriostatic water first, dilute acetic acid if it stays cloudy. Refrigerate once mixed. Don’t combine with high-dose vitamin C in the same preparation.

Reported side effects

Scalp irritation or redness (most common)
Itching or dryness at the application site
A faint greenish tint on very light hair
Needle-site redness or bruising with mesotherapy
Uncommon contact allergy to copper or preservatives

Track progress with standardised photos every 4–8 weeks. Hair change is too slow to judge by eye from day to day.

Who should avoid it

Broken, inflamed or infected scalp
Copper allergy; Wilson’s disease or other copper disorders
Don’t inject copper peptides systemically or stack them
Pregnancy: low concern topically, but ask a doctor

Regulatory status checked Oct 2026

Body	Status	Detail
FDA (US)	Cosmetic ingredient	Not a drug; not part of the peptide reclassification.
EMA (EU)	Cosmetic ingredient	—
CDSCO (India)	Not approved as drug	—
WADA	Not named	Topical use is no doping concern.

The NexGen read

Low risk and low proof

AHK-Cu is a sensible cosmetic hair ingredient with a tidy lab rationale. Expect cosmetic-level results, give it months, and don’t inject it.

References

Pyo HK, Yoo HG, Won CH, et al. The effect of tripeptide-copper complex on human hair growth in vitro. Arch Pharm Res. 2007;30(7):834–839. PMID 17703734