PreclinicalCopper peptide (hair and skin)

AHK-Cu

Copper tripeptide-3

Common dose: Topical 0.01–0.2% serum
Cycle: Continuous
Vial sizes: 50, 100 mg

A synthetic copper-binding tripeptide related to GHK-Cu, used mainly in topical hair-growth serums.

Evidence. One lab study on donated human hair follicles (2007). No human trials by any route.

Status

Approval: Not approved as a drug in the US or EU; used as a cosmetic ingredient.
Sport (WADA 2026): Not banned in sportNot named on the 2026 list. USADA lists the related cosmetic peptide tripeptide-1 (GHK) as not prohibited.

Sport status follows the WADA Prohibited List in force since January 1, 2026; athletes should confirm with their anti-doping organization. Checked October 5, 2026. Status of every compound.

How it works

AnimalMainly from cell and animal studies; not shown in people.

Not known

Its target is unknown, as is whether enough passes through scalp skin to reach follicles, or whether the lab effect means more hair in people.

Protocol

Community

Topical serum: roughly 0.01–0.2% (100–2,000 ppm), applied once daily. Reported strengths vary about 20-fold.

Community

Injection: forum reports only, with no basis for a dose.

Frequency: Once daily (topical)
Route: Topical (scalp and skin)
Cycle: Continuous; judge results after 8–12 weeks.
Continuous, shown over 26 weeks

Common protocols

The ways AHK-Cu is most often run, each tagged with where it comes from.

Scalp solution

Community

Dose: 0.2% (2,000 ppm)
How often: Once daily
How long: Judge at 8–12 weeks

A supplier’s reference scalp formula uses 0.2% in water, kept at pH 5.5–7.0. This is the top of the reported range.

Lower-strength serum

Community

Dose: 0.01–0.1% (100–1,000 ppm)
How often: Once daily
How long: Continuous

Lower end of the reported range. No human study has compared strengths.

Taking it

Where it goes

Applied to a clean scalp or skin as a leave-on serum or spray. Topical only; cosmetic serums aren’t sterile and must never be injected.

If you miss a dose

Nothing special. Skip it and apply as usual the next day.

What to expect

First 8 weeks
Little visible change is typical, since hair grows slowly.
Community
8–12 weeks
The point where users judge shedding or density. No human trial has measured results.
Community

Side effects and what to do

Scalp or skin irritation, itching or redness

Patch-test first. Stop if it doesn’t settle.

Allergic rash

Avoid with a copper allergy or Wilson’s disease. Stop at the first sign of a rash.

Infection or harm from injecting a cosmetic serum

Never inject topical products; they aren’t sterile.

Stop and get medical help

Stop and see a doctor for a spreading rash, blistering, swelling or hives.

Who should avoid it

No product label covers AHK-Cu, so these come from human studies and from precautions based on how it works. Most important first.

Wilson’s disease or other copper disorders: PrecautionIt carries copper, and in Wilson’s disease the body can’t clear copper normally. How much passes through the skin hasn’t been measured.
Known copper allergy: PrecautionCopper is a very weak skin allergen, a review found, but in a few people it causes real allergic reactions.
Pregnancy or breastfeeding: PrecautionNo human safety data exist.
Anyone thinking of injecting a serum: PrecautionTopical serums aren’t sterile, and AHK-Cu has never been tested by injection.

Interactions

No interaction studies have been published, and no product label lists any.

Precaution: follows from how it works or from a related drug, and hasn’t been tested. This isn’t a complete list: a pharmacist or doctor can check a specific medicine or condition.

Tracking and pairing

Worth tracking

Scalp irritation or rash

Often paired with

Usually run on its own.

Human studies

No published human studies of AHK-Cu turned up in our October 2026 review. The evidence note at the top of this page sums up what is known.

Limits of the evidence

AHK-Cu has no human trials by any route. Its only published evidence is a 2007 lab study on donated hair follicles and cultured follicle cells. Whether serums grow hair, how much reaches the follicle, and long-term safety on the scalp are untested, and product strengths vary widely.

Serum strength

AHK-Cu is used on the skin, so the math is a dilution, not a syringe dose.

Powder	Serum volume	Strength	Percent	ppm
50 mg	25 mL	2 mg/mL	0.2%	2,000 ppm
50 mg	50 mL	1 mg/mL	0.1%	1,000 ppm
50 mg	100 mL	0.5 mg/mL	0.05%	500 ppm
50 mg	250 mL	0.2 mg/mL	0.02%	200 ppm

For a serum, dissolve the powder in a water-based carrier. Make small batches and keep them cold and dark; finished serum breaks down with light and air.

Datasheet

Half-life: No reliable value has been published.
Type: Peptide, 3 amino acids
Molecular weight: 451.4 g/mol
Formula: C₁₅H₂₄ClCuN₆O₄
Sequence: AHK
Storage before use: Freezer (about −20 °C) for long-term storage, kept dry and away from light.
After mixing or opening: Fridge (2–8 °C); use within about 4 weeks.

Molecule: PubChem CID 168431292 (AHK-Cu, copper complex as monohydrochloride, CAS 682809-81-0); free AHK tripeptide is CID 7408502, 354.4 g/mol
Storage: Community Common research-peptide practice; no manufacturer stability data found.

Every compound side by side: the half-life chart and the storage chart.

Cautions

No human trials.
Topical serums aren’t sterile. Never inject them.
Patch-test first. Avoid with copper allergy or Wilson’s disease.

Questions

What is AHK-Cu?

A synthetic copper-binding tripeptide related to GHK-Cu, used mainly in topical hair-growth serums.

How does AHK-Cu work?

AHK-Cu, a copper-carrying tripeptide related to GHK-Cu, lengthened donated human hair follicles kept alive in the lab in the only published study, and made dermal papilla cells multiply, with signs of less cell death. These cells sit at the base of a follicle and steer hair growth. No study has tested it on a living scalp. Its target is unknown, as is whether enough passes through scalp skin to reach follicles, or whether the lab effect means more hair in people.

Is AHK-Cu FDA-approved?

Not approved as a drug in the US or EU; used as a cosmetic ingredient.

What is the usual AHK-Cu dose?

From community reports, not established: Topical serum: roughly 0.01–0.2% (100–2,000 ppm), applied once daily. Reported strengths vary about 20-fold. Injection: forum reports only, with no basis for a dose. These are the amounts sources reference, not recommendations.

Who should avoid AHK-Cu?

No product label covers AHK-Cu, so these come from human studies and from precautions based on how it works. Wilson’s disease or other copper disorders: It carries copper, and in Wilson’s disease the body can’t clear copper normally. How much passes through the skin hasn’t been measured. Known copper allergy: Copper is a very weak skin allergen, a review found, but in a few people it causes real allergic reactions. Pregnancy or breastfeeding: No human safety data exist. The “Who should avoid it” section lists 1 more group.

How should AHK-Cu be stored?

Before mixing: Freezer (about −20 °C) for long-term storage, kept dry and away from light. After mixing: Fridge (2–8 °C); use within about 4 weeks. This is common practice; no product label covers it.

Is AHK-Cu banned in sport?

No. Not named on the 2026 list. USADA lists the related cosmetic peptide tripeptide-1 (GHK) as not prohibited.

Has AHK-Cu been studied in people?

No published human studies turned up in our October 2026 review. The evidence note at the top of this page sums up what is known.

Sources

Pyo et al., tripeptide-copper complex and human hair growth in vitro (2007) PMID 17703734

For how it works, who should avoid it and the limits of the evidence

Fage et al., copper hypersensitivity, review (Contact Dermatitis 2014) PMID 25098945

Doses tagged Community come from public dosing guides and user reports, checked against at least two of them. Those sites aren’t named here because many of them sell peptides or earn commissions on them.

By Vial Guide editorsLast reviewed October 5, 2026

How we review