Copper signaling for follicle renewal
A copper-bound tripeptide that stimulates fibroblast proliferation and follicle signaling.
Educational content. This page describes AHK-Cu for informational purposes only and is not medical advice, diagnosis, or treatment. Consult a licensed provider before starting, stopping, or modifying any therapy.
Reduces caspase-3 activity by 42.7% and PARP cleavage by 77.5% in dermal papilla cells, shifting the Bcl-2/Bax ratio toward survival and shielding hair follicle command centers from programmed cell death.[1]
Significantly increases human hair follicle elongation at picomolar to nanomolar concentrations over 12 days in organ culture, with dose-dependent proliferation of dermal papilla cells.[1]
AHK-Cu (L-alanyl-L-histidyl-L-lysine copper complex), also known as Copper Tripeptide-3, is a synthetic tripeptide bound to a divalent copper ion. It consists of alanine, histidine, and lysine chelated to Cu2+ with high affinity. The histidine residue's imidazole side chain plays the central role in copper coordination, while the lysine amino group provides additional binding stability.
AHK-Cu is a structural analog of GHK-Cu (Copper Tripeptide-1), differing only at position 1 where alanine replaces glycine. This substitution adds a methyl group that creates a slightly more rigid copper-binding pocket and may reduce spontaneous copper dissociation. Unlike GHK-Cu, which occurs naturally in human plasma, saliva, and urine, AHK-Cu is entirely synthetic with no evidence of endogenous occurrence. Its primary research focus has been on hair follicle biology.
AHK-Cu's best characterized mechanism involves stimulation of dermal papilla cells, the specialized fibroblasts that serve as the signaling center for hair follicle morphogenesis and cycling. At picomolar to nanomolar concentrations, it promotes dermal papilla cell proliferation and protects these cells from apoptosis through elevation of the Bcl-2/Bax ratio and suppression of the caspase-3/PARP cleavage cascade.
The peptide also modulates key growth factors in follicle tissue. It upregulates vascular endothelial growth factor (VEGF), promoting angiogenesis and blood supply to follicles, while downregulating transforming growth factor beta-1 (TGF-beta1), which normally pushes follicles from the active growth phase into the resting phase.
Critically, AHK-Cu shows a biphasic dose response. It is effective at extremely low concentrations (10^-12 to 10^-9 M) but becomes inhibitory at higher concentrations (10^-8 M and above). This means more is not better, and proper formulation is important for maintaining the effective concentration range.
Copper signaling for follicle renewal
AHK-Cu delivers bioavailable copper to dermal papilla cells while activating anti-apoptotic signaling (elevated Bcl-2/Bax ratio, reduced caspase-3 and PARP cleavage). It upregulates VEGF for follicle blood supply, downregulates TGF-beta1 to extend the growth phase, and supports copper-dependent enzymes including lysyl oxidase and superoxide dismutase.
Key studies supporting the therapeutic use of this peptide.
Hair follicle elongation significantly increased at 10^-12 to 10^-9 M over 12 days (p < 0.001). Dermal papilla cell proliferation increased dose-dependently. Caspase-3 reduced 42.7% and PARP cleavage reduced 77.5% (both p < 0.05). Concentrations at 10^-8 M and above inhibited growth.
Pyo HK, Yoo HG, Won CH, et al. — Arch Pharm Res, 30(7):834-839 (2007) · PubMed
Copper tripeptide complexes from the same family as AHK-Cu stimulated hair follicle activity in the mouse model, supporting the class-wide effect of copper peptides on follicle biology.
Trachy RE, Fors TD, Pickart L, Uno H — Ann N Y Acad Sci, 642:468-469 (1991) · PubMed
The structurally related GHK-Cu produced concentration-dependent increases in collagen, DNA, glycosaminoglycans, and elastin. Collagen synthesis was stimulated 2-fold more than non-collagen protein synthesis. Control tripeptide without copper had no effect.
Maquart FX, Bellon G, Chaqour B, et al. — J Clin Invest, 92(5):2368-2376 (1993) · PubMed
Typical protocols used in clinical practice. Always consult a licensed provider for personalized dosing.
Topical (serum/solution)
Topical (serum/solution): Effective at extremely low concentrations. Higher concentrations are inhibitory. Start with lower concentrations.
AHK-Cu shows a biphasic dose response: effective at picomolar to nanomolar concentrations but inhibitory at 10^-8 M and above. Formulation must maintain the effective concentration window at the tissue level.
No human clinical trials have established a validated dosing protocol. All concentration guidance comes from a single ex vivo/in vitro study and general copper peptide class data.
AHK-Cu is reportedly stable at pH 4.5 to 6.8, a wider range than GHK-Cu which degrades below pH 5.5. Avoid combining with strong exfoliating acids or low-pH vitamin C formulations that may destabilize the copper-peptide bond.
No formal toxicology studies have been published specifically on AHK-Cu. All safety information is extrapolated from one in vitro study and general copper peptide class data.
The related peptide GHK-Cu has an extensive safety record with topical use, and its toxic dose is approximately 300 times the therapeutic dose. AHK-Cu likely shares a similar safety margin for topical application.
No long-term safety data exists. The single published study on AHK-Cu (Pyo et al. 2007) has not been replicated or extended to in vivo or human testing in the years since publication.
See how AHK-Cu compares to peptides with overlapping benefits.
| Peptide | Primary Use | Administration | Cycle Length | Key Differentiator |
|---|---|---|---|---|
| AHK-Cu | Hair & Skin Regeneration | Topical | 8 to 12 weeks | Hair follicle-focused copper peptide with demonstrated dermal papilla cell protection and a biphasic dose response requiring precise formulation |
| SS-31 (Elamipretide) | Mitochondrial Restoration & Anti-Aging | Injection (daily) | Continuous (weeks to months) | Only peptide that directly targets cardiolipin on the inner mitochondrial membrane to restore electron transport chain efficiency |
| Melanotan 1 (Afamelanotide) | Photoprotection & Pigmentation | Subcutaneous Implant | Every 60 days (ongoing) | The only FDA-approved melanocortin agonist, combining eumelanin induction with UV-independent DNA repair through a selective MC1R mechanism |
| GHK-Cu | Anti-Aging & Recovery | Topical, Injection | 8–12 weeks | Only peptide demonstrated to modulate ~31% of human genes, epigenetically resetting cellular function toward a younger phenotype |
| Sermorelin | Anti-Aging & GH Restoration | Injection (daily) | 3–6 months | Only GHRH analog with FDA approval history and multi-decade safety record, uniquely preserving natural GH feedback |
Current FDA classification and compounding eligibility.
This substance does not appear on any FDA bulk drug substances list. It is classified as research-use only and cannot be legally compounded for human use.
AHK-Cu does not appear on any FDA 503A or 503B bulk drug substances list. It has no NDA, BLA, or IND. It has never been nominated for FDA evaluation. Compounding pharmacies cannot legally compound AHK-Cu for human use under current FDA regulations. Available only as a research-use or cosmetic ingredient.
Last verified April 12, 2026. PepHookup tracks public FDA actions. This is not legal or medical advice.
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