Compounds / AHK-Cu
AHK-Cu
Also known as: Copper Tripeptide-3; AHK-Cu; alanyl-histidyl-lysine copper(II) complex; Ala-His-Lys-Cu; CAS 767286-83-9
Primary research focus: Topical cosmetic use (hair and scalp support, skin conditioning)
Last updated July 2026 · Reviewed against FDA labeling and published research.
What is AHK-Cu?
AHK-Cu (Copper Tripeptide-3) is a synthetic copper-binding tripeptide, alanyl-histidyl-lysine complexed with copper(II). It is used topically as a cosmetic ingredient, most often in hair and scalp products, and is a close relative of GHK-Cu (Copper Tripeptide-1) with alanine substituted for glycine at the first position. It is a cosmetic active, not an FDA-approved drug, and its hair-related evidence is preclinical (cell-culture and ex vivo).
In laboratory studies, AHK-Cu is reported to stimulate proliferation of dermal papilla cells and elongation of hair follicles ex vivo at very low (picomolar to nanomolar) concentrations, with upregulation of vascular endothelial growth factor (VEGF), suppression of transforming growth factor-beta1 (TGF-beta1), and a shift in the Bcl-2/Bax ratio that reduces programmed cell death in follicular cells. Copper peptides are also associated in the broader literature with collagen and extracellular-matrix support. These are cosmetic and preclinical findings, not demonstrated clinical hair-loss treatment effects.
How it’s supplied
Supplied as a cosmetic raw material: a light blue fine powder (about 99 percent) for formulators, and as liposomal liquids and finished topical serums or sprays. It is not an injectable or ingestible drug product. Typical finished hair serums contain roughly 100 to 500 ppm of Copper Tripeptide-3.
Potential Benefits and Side Effects
Effects reported in published research. Not a promise of results, and not medical advice.
- Reported in preclinical (cell-culture and ex vivo) research and cosmetic-use contexts; not proven clinical drug effects.
- Stimulation of dermal papilla cell proliferation and hair follicle elongation in laboratory models.
- Reduced follicular cell apoptosis (via Bcl-2/Bax modulation) in vitro.
- Upregulation of VEGF and suppression of TGF-beta1 in follicular cells.
- General support of collagen and extracellular-matrix quality attributed to copper peptides.
- As a topical cosmetic, generally well tolerated when formulated appropriately.
- Possible local skin or scalp irritation, redness, or sensitization, particularly with copper sensitivity.
- No systemic adverse-effect profile is established for this use.
Warnings and contraindications
Important safety information. This is not exhaustive — read the full prescribing information and consult your prescriber or pharmacist.
- This is a topical cosmetic ingredient, not an FDA-approved drug; the following are general cosmetic-use cautions, not drug label warnings.
- For external use only; avoid the eyes and broken skin.
- Excess copper in a formulation can cause a vivid blue color and may increase irritation; formulate within recommended use levels.
- Patch testing is advisable, as copper peptides can cause local irritation or sensitization in some individuals.
- Hair-growth effects are based on laboratory data; clinical proof of hair regrowth in people is limited.
- Not evaluated for safety in pregnancy or breastfeeding for this specific use.
- Not established as a drug; the following are precautionary for topical cosmetic use.
- Known hypersensitivity to copper or to copper peptides.
- Application to broken, inflamed, or infected skin.
Reconstitution Steps
How to prepare the lyophilized vial. Confirm specifics with your pharmacist or prescriber.
- This is a topical cosmetic ingredient; the steps below describe dissolving the powder into a formulation, not preparing an injection.
- Confirm the target use level (for example, a percentage or ppm of Copper Tripeptide-3) for your formulation.
- Weigh the powder accurately on a calibrated scale.
- Add the powder to the water phase of the formulation, not to oils or anhydrous phases.
- Keep the formulation temperature below about 40 degrees C to protect the peptide.
- Stir gently until fully dissolved; the solution will take on a light blue tint from the copper.
- Note the resulting concentration so it matches the calculator on this page.
- Add an appropriate preservative system and complete the formulation, then store as directed.
US regulatory status
Classifications are public record but can change. For reference only, not legal advice.
Development: AHK-Cu (Copper Tripeptide-3) was studied for hair biology in the mid-2000s; the most cited work is Pyo et al. (Archives of Pharmacal Research, 2007), which reported follicle elongation and dermal papilla cell proliferation ex vivo and in vitro. It is marketed as a cosmetic ingredient rather than developed as a drug, and there is no FDA drug-development program, IND, or registered clinical trial for it. Note that AHK-Cu is distinct from GHK-Cu; only GHK-Cu appeared on the FDA peptide compounding (Category 2) list.
Notes: AHK-Cu is regulated as a cosmetic ingredient (INCI: Copper Tripeptide-3), not as a drug, and it has no FDA drug approval. Cosmetic claims are limited to appearance and conditioning; therapeutic hair-loss claims would place a product into drug territory. As a cosmetic active it is outside the 503A and 503B drug-compounding pathways. It is not a controlled substance.
International status
Pharmacokinetics
Storage and handling
Important Notes
Practical considerations for consistency and safety.
- AHK-Cu (Copper Tripeptide-3) is different from GHK-Cu (Copper Tripeptide-1); they share copper binding but differ by one amino acid and in their evidence base.
- The hair-related evidence is preclinical (ex vivo follicle culture and dermal papilla cells); clinical proof of hair regrowth in people is limited.
- It is a cosmetic ingredient, not an FDA-approved drug, and should not be marketed with drug claims.
- Products should be formulated within recommended use levels; overly blue products often signal excess copper.
Lifestyle Factors
- Used topically; a clean scalp free of heavy product buildup may improve delivery to the follicle.
- Often combined in cosmetic routines with other actives such as minoxidil (as separate products) under user discretion.
References
Related compounds
Important disclaimer
This page is an educational reference, not medical advice, a diagnosis, or a treatment recommendation, and not a substitute for your prescriber or pharmacist. Approval and regulatory status varies by compound and can change. Always confirm against current prescribing information and consult a qualified healthcare professional before making any decision about a medication.