GHK-Cu vs AHK-Cu: What One Amino Acid Changes
GHK-Cu and AHK-Cu are both copper-complexed tripeptides, both end in histidine-lysine, and differ in exactly one position: the first residue is glycine in GHK-Cu and alanine in AHK-Cu. One methyl group apart. Because the names are a single letter apart too, they are mixed up constantly in supplier listings and secondary write-ups — and the research literature on them points in noticeably different directions, so the confusion is not harmless.
| GHK-Cu | AHK-Cu | |
|---|---|---|
| Sequence | GHK-CuGlycyl-L-histidyl-L-lysine (Gly-His-Lys), copper-complexed | AHK-CuAlanyl-L-histidyl-L-lysine (Ala-His-Lys), copper-complexed |
| Structural difference | GHK-CuGlycine at position 1 — the smallest amino acid, no side chain | AHK-CuAlanine at position 1 — glycine plus a single methyl group |
| Occurrence | GHK-CuOccurs naturally in human plasma; plasma concentration is reported to decline with age, which is the origin of much of the interest in it | AHK-CuNot established as a naturally occurring human plasma peptide in the same way; studied as a synthetic analogue |
| Primary research focus | GHK-CuExtracellular matrix remodelling, collagen and glycosaminoglycan synthesis, wound-healing and antioxidant models; a notably broad gene-expression literature | AHK-CuAngiogenesis and vascular endothelial growth factor signalling; dermal papilla and hair-follicle models |
| Copper role | GHK-CuCopper is integral to the proposed mechanism, not a carrier — the apo-peptide and the complex are not treated as equivalent in the literature | AHK-CuAlso studied as a copper complex, with the metal ion similarly treated as part of the active species |
| Literature volume | GHK-CuThe larger body of work by a wide margin, spanning decades | AHK-CuSubstantially smaller and more narrowly focused |
| Handling | GHK-CuCopper complexes are light- and oxidation-sensitive; see storage conditions and how long peptides last | AHK-CuSame considerations as GHK-Cu — treat both as light-sensitive copper complexes |
Takeaway
The two are not interchangeable despite being one methyl group apart. GHK-Cu carries the far larger literature and is studied principally for extracellular matrix and wound-repair biology; AHK-Cu research clusters instead around angiogenic signalling and follicular models. If a supplier listing, a formulation ingredient list or a secondary article uses the names loosely, assume it has not distinguished them deliberately and go back to the certificate of analysis — the sequence on the COA is the only thing that settles which compound is actually in the vial.
Research-profile comparison for laboratory reference only — not a usage, dosing, or stacking guide. See our legal & compliance hub for the regulatory position on either compound.
Common Questions
What is the difference between GHK-Cu and AHK-Cu?
A single amino acid at the first position: glycine in GHK-Cu, alanine in AHK-Cu. Both are copper-complexed tripeptides ending in histidine-lysine. Despite that closeness, GHK-Cu research centres on extracellular matrix and wound-healing biology while AHK-Cu research centres on angiogenic signalling and hair-follicle models.
Is AHK-Cu just a cheaper version of GHK-Cu?
No — they are distinct compounds with distinct research literatures, not grades of the same thing. Pricing differences reflect synthesis and demand, not potency equivalence, and nothing in the published work supports treating one as a substitute for the other.
How do I tell which one I actually received?
The certificate of analysis is the only reliable answer: it states the sequence and the measured molecular weight, and the two differ by 14 daltons — one methyl group. Our guide on reading a COA explains how to check a reported mass against the theoretical one, and every PepcoLab batch is checkable by lot number at /verify.
Does the copper matter, or is it just a delivery vehicle?
In both compounds the copper ion is treated in the literature as part of the active species rather than as a carrier. Research on the copper-free peptide and on the complex is not interchangeable, which is one reason a COA that does not specify the complexed form leaves a real ambiguity.
Do copper peptides need different storage from other peptides?
They warrant particular care with light and oxidation on top of the usual lyophilised-peptide considerations. The general framework is in our storage guide, with stability timeframes by state in how long peptides last.