{"id":"ahk-cu","name":"AHK-Cu","aliases":["copper tripeptide AHK","Ala-His-Lys copper","alanyl-histidyl-lysine copper","copper peptide (hair)"],"url":"https://lyoresearch.com/compounds/ahk-cu","class":{"id":"healing-peptides","name":"Tissue-repair peptides","url":"https://lyoresearch.com/classes/healing-peptides"},"summary":"AHK-Cu is a copper-bound tripeptide — alanine, histidine, lysine — marketed for hair growth in serums and, increasingly, as an injectable alongside GHK-Cu. The entire evidence base is one 2007 laboratory study in which it lengthened human hair follicles kept alive in culture and made dermal papilla cells divide. No trial has applied it to a person's scalp, let alone injected it. It is a legal cosmetic ingredient and nothing more; GHK-Cu, by contrast, has small human trials for topical skin use.","overall_grade":"D","overall_grade_meaning":"no human evidence","human_trials":"0 — one ex vivo follicle study","regulatory_status":"Cosmetic ingredient; no clinical evidence","molecule":{"formula":"C15H24ClCuN6O4-","molecular_weight":"451.39","cas":"682809-81-0","pubchem_cid":168431292,"note":"PubChem record is the hydrochloride"},"pharmacokinetics":{"basis":"none","route":"Topical as sold; no human study","half_life":"No human pharmacokinetic data","licensed_regimen":null,"product":null,"source":null},"outcomes":[{"outcome":"Hair growth (topical, in people)","grade":"D","grade_meaning":"no human evidence","effect_size":"not measurable","adverse":false,"human_studies":"0 controlled","evidence":"No human trial of any design. The single study kept plucked human follicles alive in a dish for a week and measured elongation.","references":[{"citation":"Pyo HK, Yoo HG, Won CH, et al. The effect of tripeptide-copper complex on human hair growth in vitro.","where":"Arch Pharm Res, 2007","url":"https://pubmed.ncbi.nlm.nih.gov/?term=Pyo+tripeptide-copper+complex+human+hair+growth+in+vitro+2007"},{"citation":"Searches of PubMed and trial registries for AHK-Cu in humans.","where":"LYO literature search, September 2026","url":"https://pubmed.ncbi.nlm.nih.gov/?term=AHK-Cu"}]},{"outcome":"Hair follicle elongation (ex vivo)","grade":"D","grade_meaning":"no human evidence","effect_size":"not measurable","adverse":false,"human_studies":"1 laboratory study","evidence":"At nanomolar concentrations AHK-Cu lengthened cultured human follicles and increased dermal papilla cell proliferation; the anti-apoptotic effect it was designed to show was not statistically significant. Laboratory evidence, not clinical.","references":[{"citation":"Pyo HK, Yoo HG, Won CH, et al. The effect of tripeptide-copper complex on human hair growth in vitro.","where":"Arch Pharm Res, 2007","url":"https://pubmed.ncbi.nlm.nih.gov/?term=Pyo+tripeptide-copper+complex+human+hair+growth+in+vitro+2007"}]},{"outcome":"Injected use (skin, hair)","grade":"D","grade_meaning":"no human evidence","effect_size":"not measurable","adverse":false,"human_studies":"None","evidence":"No study of any kind. An injected copper peptide has no established pharmacology in humans.","references":[]},{"outcome":"Safety in humans","grade":"D","grade_meaning":"no human evidence","effect_size":"not measurable","adverse":true,"human_studies":"Cosmetic-use experience only","evidence":"Topical use as a cosmetic ingredient has no reported safety signal; injected use has no data at all.","references":[]}],"regions":[{"region":"European Union","status":"Cosmetic ingredient","note":"Permitted in cosmetics; no medicinal authorisation. Injectable products are unauthorised medicines."},{"region":"United States","status":"Cosmetic ingredient","note":"Sold in cosmetics without drug approval; injectable versions are unapproved drugs."},{"region":"United Kingdom","status":"Cosmetic ingredient","note":"Same position; injectable use is unlicensed."},{"region":"Australia","status":"Cosmetic ingredient","note":"Topical cosmetic use permitted; injectables not on the ARTG."},{"region":"Canada","status":"Cosmetic ingredient","note":"Topical cosmetic use; no DIN for any injectable."},{"region":"Sport (WADA)","status":"Not named","note":"Not on the Prohibited List."}],"faq":[{"q":"Does AHK-Cu grow hair?","a":"In a dish, it lengthened cultured follicles in one study. On a person, it has never been tested. That is the whole evidence base."},{"q":"AHK-Cu or GHK-Cu?","a":"GHK-Cu has small human trials for topical skin use and a much larger laboratory literature; AHK-Cu has one ex vivo study and nothing in people. For injected use, neither has any human evidence."},{"q":"Is injecting copper peptides safe?","a":"No study has looked. Topical cosmetic use has no known safety signal; injection is a different exposure with no data."}],"references":[{"cite":"Pyo HK, Yoo HG, Won CH, et al. The effect of tripeptide-copper complex on human hair growth in vitro.","where":"Arch Pharm Res, 2007","url":"https://pubmed.ncbi.nlm.nih.gov/?term=Pyo+tripeptide-copper+complex+human+hair+growth+in+vitro+2007","note":"Ex vivo follicles and cultured dermal papilla cells; no human subjects."},{"cite":"Searches of PubMed and trial registries for AHK-Cu in humans.","where":"LYO literature search, September 2026","url":"https://pubmed.ncbi.nlm.nih.gov/?term=AHK-Cu","note":"No clinical study identified."}],"last_reviewed":"2026-09-10","literature_searched_to":"2026-09-10","changelog":[{"date":"2026-09-10","note":"Initial publication. Grade D: one ex vivo study, no human trial."}],"license":"CC BY 4.0 — cite as “LYO Research” with a link.","methodology":"https://lyoresearch.com/methodology"}