AHK-Cu

AHK-Cu is made of three amino acids, alanine, histidine and lysine, bound to a copper ion. It differs from the better-known copper peptide GHK-Cu by a single amino acid: alanine in place of glycine. Early work on GHK noted that several tripeptides sharing the histidine-lysine pair behaved similarly in cell culture (Pickart 1980), which is part of why related copper peptides were explored.

In practice, AHK-Cu appears mostly in topical hair-care and skincare products marketed for thinning hair. The research base is very thin. Searching PubMed, we found one study on AHK-Cu itself, from a dermatology group at Seoul National University, which tested it on human hair follicles kept alive in the lab and on cultured hair-root cells (Pyo 2007). We also found one cell study of a different molecule built from the same three amino acids, linked to vitamin C and without copper (Jung 2018).

We could not find any animal study, human trial, or study of injected AHK-Cu. Claims that it regrows hair or repairs skin in people are not supported by published evidence that we could locate.

• Type: synthetic tripeptide (alanine-histidine-lysine) bound to copper; a close relative of GHK-Cu.
• Studied for: hair follicle growth, in the lab only.
• Strongest evidence: one lab study on human hair follicles and cells. No animal or human studies found.
• Legal status: used as a cosmetic ingredient; not approved as a drug in the US.

At a glance: 2 studies report a dose (2 in cells).

Only one study looked at how AHK-Cu might act, and only in cells:

• More hair-root cells: AHK-Cu increased the growth of dermal papilla cells in culture (Pyo 2007).
• Less programmed cell death: it raised the ratio of the survival protein Bcl-2 to the cell-death protein Bax and lowered the active forms of caspase-3 and PARP, markers of programmed cell death (Pyo 2007).

1. Wash your hands and work on a clean, uncluttered surface. Let a refrigerated vial reach room temperature so the stopper is easier to pierce.
2. Wipe the rubber stopper of the peptide vial and of the bacteriostatic water with a fresh alcohol swab, and let them air-dry.
3. Draw the chosen volume of bacteriostatic water into a sterile syringe. With 2 mL, a 50 mg vial ends up at 25,000 mcg/mL, or 250 mcg per U-100 unit.
4. Insert the needle through the stopper and let the water run slowly down the inside wall of the vial, not straight onto the powder.
5. Swirl or roll the vial gently until the powder dissolves. Do not shake it: foaming can damage some peptides.
6. Check the solution against the light. It should be clear; cloudiness or particles mean something is wrong with the vial or the water.
7. Write the date and the volume of water on the label. Every unit calculation later depends on that volume.
8. Store the reconstituted AHK-Cu vial in the refrigerator, away from light.

• A U-100 insulin syringe holds 1 mL in 100 units, so each unit is 0.01 mL. The marks measure volume, not peptide.
• Syringes come in 0.3 mL (30 units), 0.5 mL (50 units) and 1 mL (100 units) sizes. The smaller ones have finer marks and are easier to read for small volumes.
• Read the volume at the top edge of the plunger's rubber seal, at eye level.
• Tap out air bubbles before reading: a bubble takes up volume and makes the reading wrong.
• Use a new sterile syringe and needle every time, and dispose of them in a sharps container.

• The peptide vial, with its certificate of analysis (COA) for that batch. See how to read a COA.
• Bacteriostatic water (water with 0.9% benzyl alcohol), which keeps a multi-use vial from growing bacteria. Sterile water has no preservative.
• Sterile syringes to add the water, and U-100 insulin syringes to measure.
• Alcohol swabs for the stoppers.
• A sharps container for used needles.
• A label or marker to write the date and the volume of water on the vial.

There are no published human safety data for AHK-Cu, and none on injected use. Its use in cosmetic products is not the same as evidence of safety, because cosmetics are not reviewed by the FDA before sale.

• Very limited evidence: one lab study does not show what happens on a real scalp or in the body.
• Product quality: AHK-Cu sold online, especially for injection, is not checked by any regulator for identity, purity, dose or sterility.
• Copper: the peptide carries copper. We could not find studies on what repeated use does to copper levels in the body.
• Injection risks: any injected product that is not sterile can cause infection or abscesses.

Before mixing

• Freeze-dried (lyophilised) peptide is the most stable form. It is usually kept refrigerated, or frozen for long storage, sealed and away from light.
• Heat, moisture and light speed up degradation. Keep the vial in its box and avoid leaving it in a car or by a window.

After mixing

• Keep the reconstituted vial refrigerated and away from light. Do not freeze it again: freezing and thawing a solution can break the peptide down.
• How long a mixed vial stays good depends on the peptide and the diluent, and for most research peptides there is no published stability data. Follow the supplier's guidance and discard any vial that turns cloudy.
• Pierce the stopper as few times as possible, and always with a new sterile needle after wiping it with alcohol.
• Write the volume of water on the label (for example "2 mL"). Without it, the unit calculations cannot be checked later.