AHK-Cu

What is AHK-Cu?

AHK-Cu (L-alanyl-L-histidyl-L-lysine copper) is a synthetic copper tripeptide built from the amino acids alanine, histidine, and lysine, plus a bound copper(II) ion. Compared to the well-known peptide GHK-Cu, it has alanine instead of glycine at position 1. That is why research on AHK-Cu focuses on stimulating hair follicles rather than on general wound healing [1].

AHK-Cu is a purely synthetic active ingredient, so it does not occur naturally in the human body. It is listed under the INCI name Copper Tripeptide-3 as a cosmetic ingredient for hair and scalp. The peptide has the CAS number 767286-83-9 and a molar mass of about 417 g/mol.

How is AHK-Cu used?

AHK-Cu is used only topically - as a serum, aqueous solution, or emulsion on the scalp and skin. Typical cosmetic concentrations range from 0.01 to 1 percent. There is no drug approval for the peptide, and no evidence-based injection form exists. The only peer-reviewed study tested the substance directly on isolated hair follicles in cell culture [1].

There is no scientific basis for injecting AHK-Cu powder under the skin. Systematic human studies on safety, dosage, and pharmacokinetics are missing. In practice, only rudimentary in-vitro data support the external, topical use.

From vial to use: preparing AHK-Cu topically

To prepare a topical AHK-Cu solution, you dissolve the blue lyophilized powder in water. Users often choose a 0.2 percent concentration:

• Starting material: 100 mg AHK-Cu powder
• Solvent: 50 mL distilled water (or a water-glycerin mixture for even distribution)
• Target concentration: 0.2% AHK-Cu solution (equivalent to 2 mg/mL)
• pH value: target range between 5.5 and 7.0, since AHK-Cu stays stable in a slightly acidic to neutral environment

A 50-mL bottle of 0.2 percent solution is theoretically enough for about 100 to 200 individual applications of 0.25 to 0.5 mL (each 0.5 to 1 mg of peptide). These amounts reflect an unverified user practice from cosmetic formulations; detailed practical steps can be found in the guides.

Prepared AHK-Cu solutions should always be stored cool and protected from light. The active ingredient loses activity over time in an aqueous environment, while the undissolved blue powder stays stable at room temperature.

How does AHK-Cu work?

AHK-Cu acts as a signaling peptide. It transports copper ions directly to target cells and activates biochemical pathways for hair shaft formation and melanin production. Copper is an essential trace element for enzymatic processes that support follicle structure and hair pigmentation.

In the in-vitro study by Pyo et al. (2007) on isolated human dermal papilla cells, four main biological effects of AHK-Cu on hair growth were identified [1]:

• Cell proliferation: AHK-Cu stimulates the multiplication of dermal papilla cells, which supports hair follicle growth.
• Apoptosis inhibition: It reduces programmed cell death in papilla cells, although this effect was not statistically significant.
• VEGF increase: It stimulates the release of VEGF (Vascular Endothelial Growth Factor), which improves blood flow and nutrient supply to the follicles.
• TGF-β1 reduction: It reduces the formation of TGF-β1, a signaling protein that prematurely shifts hair follicles into the resting phase (telogen).

In the experiments by Pyo et al. (2007), these cellular effects occurred already at very low AHK-Cu concentrations in the range of 10^-12 to 10^-9 moles per liter (picomolar to nanomolar) [1].

How effective is AHK-Cu?

The scientific evidence for the effectiveness of AHK-Cu is very thin: nearly all available findings come from a single in-vitro and ex-vivo study by Pyo et al. from 2007 on cell cultures and hair follicles [1]. No clinical studies on human subjects have been published to date.

Neither controlled phase I to III studies nor independent replication studies exist for AHK-Cu. The scientific data basis is significantly smaller than for the related copper peptide GHK-Cu, and alleged advantages for hair growth are not supported by direct comparative studies.

AHK-Cu vs. GHK-Cu - what is the difference?

Although AHK-Cu and GHK-Cu both belong to the family of copper tripeptides, they differ significantly in amino acid sequence, origin, and research focus:

For detailed information, the overview of GHK-Cu is available, while the peptide library offers a classification of other peptide active ingredients.

Side effects and safety profile

Because clinical human studies are missing, the toxicological safety profile of AHK-Cu is only very limitedly researched. The cell study by Pyo et al. (2007) showed no cytotoxicity on dermal papilla cells at effective doses, but it does not allow conclusions about tolerability in humans [1].

Existing safety assessments by the Cosmetic Ingredient Review (CIR), which consider concentrations below 10 ppm as safe, primarily refer to Copper Tripeptide-1 (GHK-Cu) and not specifically to Copper Tripeptide-3 (AHK-Cu) [2]. A direct transfer of these CIR limits is scientifically unverified.

With local application on the scalp, side effects such as redness, burning, itching, or contact dermatitis can occur, which is why people with a copper allergy should avoid AHK-Cu. Systemic copper exposure is unlikely with cosmetic use, whereas non-topical applications such as injections carry unpredictable health risks.

What is NOT known?

• No clinical studies: No phase I, II, or III investigations in humans available.
• Unknown pharmacokinetics: Skin penetration, metabolism, half-life, and excretion are not scientifically documented.
• Lack of replication: The study results by Pyo et al. have not yet been independently reproduced.
• No direct comparison of effects: A scientific head-to-head comparison between AHK-Cu and GHK-Cu is missing.
• Lack of long-term data: No studies on long-term safety and chronic use.
• No injection data: Subcutaneous or intramuscular injections lack any scientific basis.

On the unregulated peptide gray market, significant product risks from contamination, underdosing, or cutting agents are looming; practical tips for minimizing risks are provided in the guide on protection when ordering.