AHK-Cu
L-Alanyl-L-Histidyl-L-Lysine Copper(II) Complex (Copper Tripeptide-3)
Synthetic copper-binding tripeptide with one direct laboratory study demonstrating ex vivo human hair follicle elongation and cultured dermal papilla cell proliferation; no clinical trials have been identified (PMID 17703734;).
Last updated: 2026-03-09
Safety Summary
No formal adverse event data exists for AHK-Cu from clinical trials. The FDA FAERS and ClinicalTrials.gov files in this project contained no peptide-specific matches. Side effect information is derived from community reports and commercial sources (;;). Copper peptides as a class have a long track record of topical safety in cosmetic use, but formal controlled safety trials specific to AHK-Cu have not been conducted.
Known Side Effects
uncommon
common
uncommon
rare
Who Should NOT Use This
Wilson's disease involves impaired copper excretion, and additional copper exposure could worsen copper accumulation. Commercial guidance lists this as a reason to avoid AHK-Cu. General copper peptide safety precaution.
Individuals with known copper allergy should avoid copper-containing peptides.
No safety data exists for AHK-Cu use during pregnancy or breastfeeding. No pregnancy-specific human studies were identified in the supplied trial or FDA search files. General precautionary avoidance recommended (;;).
Low-pH actives may destabilize copper peptides and reduce efficacy. Commercial sources recommend separating application or avoiding concurrent use.
Talk to Your Doctor
Before considering AHK-Cu, discuss it with your healthcare provider. Ask about potential interactions with your current medications, whether it is appropriate for your health conditions, and what monitoring may be needed.
Sources: [1-2]
Evidence Assessment
Tier 5: All direct evidence for AHK-Cu comes from a single ex vivo/in vitro study (PMID 17703734, Pyo et al. 2007). This study used human hair follicle organ culture (ex vivo) and cultured dermal papilla cells (in vitro). A 2021 narrative review cited the same findings but did not add new controlled human data (PMID 34377956). No animal studies, no Phase 1 or Phase 2 clinical trials, and no randomized controlled trials have been published on AHK-Cu specifically. The ClinicalTrials.gov search returned zero registered trials. The evidence base consists of a single peer-reviewed primary publication with no replication studies.
1The effect of tripeptide-copper complex on human hair growth in vitroPMID 17703734
Pyo HK, Yoo HG, Won CH, Lee SH, Kang YJ, Eun HC, Cho KH, Kim KH - Archives of Pharmacal Research (2007) - ex vivo and in vitro study - Isolated human hair follicles (ex vivo organ culture) and cultured human dermal papilla cells; exact counts not stated in the abstract
AHK-Cu at 10^-12 to 10^-9 M stimulated elongation of human hair follicles ex vivo and proliferation of DPCs in vitro. The tripeptide-copper complex elevated VEGF production and decreased TGF-beta1 secretion by dermal fibroblasts. At 10^-9 M, AHK-Cu elevated Bcl-2/Bax ratio and reduced cleaved caspase-3 and PARP levels, suggesting anti-apoptotic effects. Annexin V/PI staining showed reduced apoptotic DPCs but the decrease was not statistically significant.
Limitations: Single study with no replication. Ex vivo/in vitro only -- no in vivo human or animal data. Sample sizes for individual experiments not reported in abstract. Statistical significance not achieved for apoptosis endpoint (Annexin V). Published in 2007 with no follow-up studies from the same or other groups.
2Topical and nutricosmetic products for healthy hair and dermal antiaging using dual-acting (2 for 1) plant-based peptides, hormones, and cannabinoidsPMID 34377956
Sadgrove NJ, Simmonds MSJ - FASEB BioAdvances (2021) - narrative review - Not applicable; review article
The review identifies AHK-Cu as a copper-peptide option in the hair and dermal literature, noting that 'AHK-Cu also yielded the same outcome in vitro, that includes reduced expression of TGF-beta1 and increased hair shaft elongation, increased expression of vascular endothelial growth factor and reduced negative growth factors' (citing PMID 17703734 as ref 27).
Limitations: Narrative review rather than original efficacy trial. AHK-Cu discussion is brief (one paragraph). Does not provide new controlled human data for the peptide.