AHK-Cu common uses, half-life, side effects and more

AHK-Cu is a synthetic tripeptide of alanine, histidine, and lysine built around a copper atom. People use it on the scalp for thinning hair in a leave-on serum or spray. Retail hair products carry it openly. The same powder also reaches buyers through research-chemical channels with no approval for human use. Some vendors package it in injectable vials. It has never been approved as a medicine anywhere. GHK-Cu is a different copper tripeptide with a much larger body of research behind it and vendors frequently mislabel one as the other. Reading the exact ingredient name is the only reliable way to tell the two apart.

• Scalp application for thinning hair and shedding
• Leave-on serums and sprays for daily use
• Post-microneedling topical in hair-loss routines
• Homemade scalp serums mixed from bulk powder
• Paired with GHK-Cu in combination hair products

Once or twice daily on the scalp

Scalp serums run about 0.1% to 2% by weight and go on once or twice daily. People leave the product on rather than rinsing it off. Results are judged at three to six months because a hair cycle takes that long to turn over. Suppliers pick their percentage for cost and irritation rather than from a dose-finding study. Retail products reach 5% to 8%. Injectable vials are sold without any established dose behind them. The injection figures in circulation are the other copper peptide's protocol with the name changed.

• Keep it away from AHA, BHA, and vitamin C products in the same routine because acid breaks the copper complex
• Continuous daily use is the norm and the on-off cycles in circulation are invented
• Applying it right after microneedling is common practice and microneedling grows hair on its own
• Most products combine it with GHK-Cu rather than selling it alone

No half-life has been measured for AHK-Cu in any species. Figures circulating for it belong to GHK-Cu.

• Local irritation, redness, or stinging where it is applied
• Allergic contact dermatitis in people already sensitized to copper
• Reactions reported for copper topicals generally rather than for this peptide specifically

AHK-Cu carries a copper atom on a three amino acid scaffold. The metal is held by the terminal amine, a backbone amide nitrogen, and the histidine ring. Copper is a cofactor for the enzymes that cross-link collagen and elastin. No receptor or binding target has been identified for AHK-Cu itself. The one published experiment bathed human hair follicles and cultured dermal papilla cells at very low concentrations. Those cells govern how long a follicle stays in its growing phase. Follicles lengthened and papilla cells multiplied. Markers of programmed cell death moved in a protective direction without the count of dying cells changing significantly. Whether the same happens in a living scalp is untested.

One laboratory study from 2007 is the entire published record. It applied the peptide to excised human hair follicles and to cultured dermal papilla cells and found growth effects at very low concentrations. No living animal or person has received AHK-Cu in any published work. Everything else rests on community use and on patent mouse experiments that never faced peer review. A hair-loss trial in 36 men circulates widely and traces back to an announcement of a study whose results were never published. Several confident-sounding studies attributed to the compound do not exist at all. Users consistently report that hair looks thicker and sheds less rather than that it grows back. Almost everyone runs it alongside GHK-Cu or microneedling. Those reports cannot be pinned on this peptide alone.

• Injecting 2 mg delivers roughly a day's worth of absorbed dietary copper and bypasses the gut's control on uptake
• People with Wilson disease or other copper metabolism disorders should avoid it
• Injection doses quoted online come from a different peptide and have no basis here
• Bulk powder from research channels has no verified purity, copper content, or sterility
• Pregnancy and breastfeeding safety is unstudied