AHK- Cu

AHK-Cu was developed as a synthetic analogue of GHK-Cu after Loren Pickart's 1973 isolation of GHK from human plasma albumin. The AHK sequence (Ala-His-Lys) was designed to retain the copper-chelating histidine-lysine motif while substituting alanine at position 1 to bias activity toward follicular rather than systemic tissue remodelling. The copper-chelating form was formally characterised and patented by ProCyte Corp (US5538945A, inventors Pallenberg, Patt, Trachy; filed 1994-06-17; granted 1996-07-23), which documented hair growth stimulation in murine intradermal injection models at 0.1–0.5 mg doses with anagen onset at day 14–20. The foundational in vitro/ex vivo characterisation was published by Pyo HK et al. in 2007 (Archives of Pharmacal Research, PMID 17703734, DOI 10.1007/BF02978833), using occipital follicles from human volunteers. The INCI designation is Copper Tripeptide-3 (CosIng); CAS 682809-81-0 for the monohydrochloride salt form. It is not naturally found in plasma at detectable levels — unlike GHK, which occurs endogenously.

AHK-Cu acts through three converging pathways. (1) DPC anti-apoptosis via Bcl-2/Bax shift: at 10⁻⁹ M, AHK-Cu elevates the Bcl-2/Bax ratio in dermal papilla cells, reducing cleaved caspase-3 by ~42.7% and cleaved PARP by ~77.5% (Pyo et al. 2007). DPC apoptosis is a driver of follicle miniaturisation in androgenetic alopecia; blocking it maintains the signalling hub needed to initiate each anagen cycle. (2) TGF-β1 suppression: AHK-Cu significantly decreases TGF-β1 secretion by dermal fibroblasts. TGF-β1 is the primary cytokine driving catagen (follicle regression) and is chronically elevated in miniaturising follicles under DHT influence; suppressing it creates an anagen-permissive microenvironment. (3) VEGF-mediated angiogenesis: AHK-Cu elevates VEGF production in fibroblasts, stimulating capillary formation and nutrient delivery to the dermal papilla. The copper ion serves as a cofactor for lysyl oxidase (crosslinks new collagen/elastin in the follicular ECM) and SOD (scavenges reactive oxygen species). Wnt/β-catenin pathway activation has been proposed in secondary sources based on VEGF and β-catenin co-upregulation seen in multi-peptide nanoliposome studies (Tian et al. 2022, J Drug Deliv Sci Technol 72:103381) though AHK-Cu's direct Wnt contribution has not been isolated in a single-compound study. Dose-response is biphasic: stimulatory at 10⁻¹² – 10⁻⁹ M, inhibitory at 10⁻⁸ – 10⁻⁷ M — a hormetic pattern consistent with copper peptides generally and with signal peptides that saturate receptor binding at excess concentrations.

PRIMARY SOURCE — PMID 17703734 (Pyo HK, Yoo HG, Won CH, Lee SH, Kang YJ, Eun HC, Cho KH, Kim KH; Archives of Pharmacal Research 2007;30(7):848–54; DOI 10.1007/BF02978833): Ex vivo human hair follicle organ culture. 240 occipital follicles from 10 healthy volunteers (age 20–35). AHK-Cu at 10⁻¹² – 10⁻⁹ M significantly elongated hair follicles (p < 0.001) and stimulated DPC proliferation (p < 0.001). At 10⁻⁹ M: caspase-3 cleavage −42.7% (p < 0.05), PARP cleavage −77.5% (p < 0.05), Bcl-2/Bax ratio shifted pro-survival. VEGF elevated in dermal fibroblasts; TGF-β1 decreased. Biphasic dose-response: concentrations ≥10⁻⁸ M inhibited elongation. Conclusion: 'AHK-Cu promotes the growth of human hair follicles through stimulation of proliferation and preclusion of apoptosis of DPCs.' The study remains the only dedicated primary research publication on AHK-Cu as a single compound in human tissue as of 2026-05-04. SECONDARY SOURCE / PATENT — US5538945A (ProCyte Corp, 1996): Murine intradermal injection data for AHK:Cu (1:1 and 2:1 molar ratios). Anagen onset 14–20 days post-injection; maximal response by day 29; active growth areas 0.5–5 cm² at injection sites. Topical AHK:Cu at 0.1–0.5% w/w showed activity; 5% concentration tested in minoxidil-comparison arm. Chemotherapy model (cytosine arabinoside): intradermal AHK:Cu retained hair in 0.25 cm radius at 0.1–0.5 mg doses. RELATED MULTI-PEPTIDE STUDY — Tian et al. 2022 (J Drug Deliv Sci Technol 72:103381; DOI 10.1016/j.jddst.2022.103381): Nanoliposomes co-loaded with copper peptide + acetyl tetrapeptide-3 + myristoyl pentapeptide-4. In C57BL/6 androgenetic alopecia mice model: upregulated VEGF and β-catenin, downregulated TGF-β1. HaCaT and HDPC proliferation stimulated; collagen III and bFGF secretion elevated. Note: multi-peptide formulation — AHK-Cu contribution cannot be isolated. RELATED DELIVERY STUDY — PMC10643103 (Liu et al. 2023, Bioactive Materials; DOI 10.1016/j.bioactmat.2023.10.002; PMID 38026438): Ionic liquid microemulsion improved GHK-Cu (structural analogue) topical delivery ~3-fold vs. PBS; in mice, outperformed minoxidil for anagen induction (6 vs. 8–9 days). Establishes that delivery vehicle critically determines copper peptide bioavailability. COMMUNITY EVIDENCE — HairLossTalk forum thread (2024, user 'TheLastHairbender'): Detailed stoichiometric analysis proposing 2.5% AHK-Cu solution at 1 mL twice daily (~23.7 mg/dose); referenced Pyo 2007 concentration window; noted the 10⁻⁸ – 10⁻⁷ M cytotoxicity ceiling. Tressless.com community: users combining AHK-Cu with topical minoxidil + dutasteride + microneedling report 'fuller and thicker hair after ~4 months' via SubQ or topical application; no controlled outcomes. Key caveat: ~35–45% of community failure reports attributed to storage excursions (>25°C during shipping) or non-sterile reconstitution rather than compound inefficacy.