Copper Tripeptide-3 (AHK-Cu) bulk powder for formulators

AHK-Cu is the copper(II) complex of the tripeptide L-alanyl-L-histidyl-L-lysine, listed by suppliers under the name Copper Tripeptide-3. Formulators who already use GHK-Cu meet it as the other copper tripeptide: the same metal chemistry, one residue changed, and a much shorter paper trail. Scalp-tonic and serum developers buy it for line extensions, and bench chemists buy it to compare the two complexes side by side.

Pepti, Guangzhou manufactures the powder and supplies it in bulk from 5 g, shipped cold-chain, with a lot certificate of analysis reporting HPLC purity and mass-spectrometry identity and a safety data sheet on request. Both the evidence base and the regulatory naming are thinner than for GHK-Cu, and this page says so plainly.

Identity: how AHK-Cu differs from GHK-Cu

The two copper tripeptides on this site share two residues and the same metal. The differences sit at position one of the chain and in the counter-ion.

• Sequence. AHK is Ala-His-Lys where GHK is Gly-His-Lys. Alanine carries a methyl group in place of glycine's hydrogen, adding one carbon and two hydrogens to the formula. The copper-binding residues are unchanged.
• Counter-ion. PubChem CID 168431292 and the Pepti listing both describe the complex as a monohydrochloride, so the weight on the COA refers to the salt, about 451.4 g/mol. The copper-free ligand weighs about 354.4 g/mol.
• Naming. Copper Tripeptide-3 is a supplier listing name. We found no CosIng record under it, so the INCI designation on your label should be confirmed by your regulatory consultant rather than copied from a catalogue. Carry the CAS number and the chemical name on paperwork meanwhile.

Appearance, solubility and handling

AHK-Cu is a blue powder. The tone varies with residual water and particle size, so colour tells you that copper is bound and nothing about purity. A powder shifted toward green or brown has met a reducing environment or moisture and should be held back until re-examined.

It dissolves in water and water-glycol mixtures to a clear blue solution, tolerates little alcohol, and does not dissolve in oils, esters or silicones, so it belongs in the water phase. The hydrochloride salt is hygroscopic: weigh quickly, close the container at once, and let a cold container warm to room temperature before opening.

Pepti stores the material at −20 °C, protected from light and moisture, and recommends the same for long-term storage. Working stock can be held at 2–8 °C within a window the formulator has confirmed.

What the published literature reports, and how little there is

A buyer should know that the AHK-Cu literature is a small fraction of what exists for GHK-Cu. For AHK-Cu we could verify one primary cell-culture paper, the one supplier pages generally cite.

Pyo and colleagues report an ex-vivo and in-vitro study in which L-alanyl-L-histidyl-L-lysine-Cu2+ was applied to human hair follicles in organ culture and to cultured dermal papilla cells. The authors describe stimulated follicle elongation and dermal papilla cell proliferation at nanomolar and lower concentrations, with changes in apoptosis markers, and propose that the effect on hair growth runs through dermal papilla cell proliferation (Pyo HK et al. Arch Pharm Res, 2007).

The public identity record is the other source: PubChem lists the copper complex hydrochloride under CID 168431292 with CAS 682809-81-0 and the formula C15H24ClCuN6O4 (PubChem CID 168431292). We were not able to verify a second peer-reviewed study of the complex itself.

One cell-culture paper is a starting point, not a claim base; statements about a finished product are substantiated by the brand in each market.

Formulation notes for the bench

The copper centre behaves as it does in GHK-Cu, so the same compatibility rules apply.

• Chelating agents compete for the copper. EDTA salts and phosphonate sequestrants bind copper(II) more tightly than a tripeptide; in a chelated base the copper migrates off the peptide over shelf life and the blue fades. Build the water phase without a strong chelator, or accept a different species in the jar.
• Reducing agents. Ascorbic acid, sodium ascorbate, glutathione and other thiols reduce copper(II) and discolour the solution. Keep them in a separate product or a two-chamber pack.
• The hydrochloride lowers pH slightly. Check a buffered base after addition. Handle the complex between about pH 5 and 7.5; copper binding loosens on the acid side and copper hydroxide precipitates on the alkaline side.
• Order of addition. Pre-dissolve in cool water or a water-glycol premix and add in the cool-down phase, below 40 °C, after preservation and pH adjustment. Use opaque or amber packs.

The use level is set by the formulator from stability and tolerance work in the buyer's own base; Pepti publishes none.

Specification and documents for this material

Each lot COA reports reverse-phase HPLC purity as area percent, a mass-spectrometry identity check against the expected weight, appearance, and the storage and retest statements. Copper content and water content are added when the buyer's specification asks for them. The SDS is issued on request.

No public batch record for AHK-Cu is listed in the Pepti COA library yet, so this page carries no record table and no lot figure to quote in advance. The lot COA is issued with the shipment and states the purity of the material you receive. For orientation, the records Pepti publishes for other compounds currently fall between 98.4% and 99.8% HPLC purity.

Public batch records

No public batch record is listed for this compound in the manufacturer's library yet. The lot you receive carries its own COA with HPLC purity, MS identity and lot number; ask for the current lot's COA with your quote. The library itself is at peptioem.com/coa.