AHK-Cu (copper tripeptide): what it is, how it is supplied, and how it differs from GHK-Cu

AHK-Cu is a tripeptide — alanine, histidine, lysine (Ala-His-Lys) — bound to one copper(II) ion. It is the close relative of GHK-Cu: the only difference in sequence is the first residue, alanine instead of glycine, which adds one methyl group. The free tripeptide (AHK) has a molecular weight of about 354 Da; the copper complex is about 418 Da.

Like GHK-Cu, it is easy to recognize on a bench:

• The color. The copper(II) ion gives the lyophilized powder a blue-to-violet tint. A white "AHK-Cu" powder is either the copper-free tripeptide or something else.
• The mass. On a certificate of analysis, mass spectrometry confirms the peptide at the expected molecular weight — 14 Da above GHK, which is how the two are told apart.

AHK-Cu appears in the literature far less often than GHK-Cu: a handful of primary papers, most of them in cultured-cell models, against decades of work on its glycine sibling. That is a fact about the documentation, not about the reagent, and it is worth knowing before ordering.

In the catalog, AHK-Cu is sold as a research reagent: a sealed vial of lyophilized powder with a batch number and a certificate of analysis. Research use only. Not for human or veterinary use.

The two are often sold on the same page and sometimes confused in listings. As objects, here is how they differ.

Because the two powders look identical, the mass spectrum on the COA is the only thing that tells them apart. A supplier that lists both should show a separate certificate for each, with an observed mass that matches the right complex.

Research AHK-Cu comes as a lyophilized (freeze-dried) powder in a glass vial closed with a rubber septum and an aluminum crimp cap. The label states the compound, the net quantity in milligrams, the lot number and the words "research use only".

The catalog offers three sizes — 50 mg, 100 mg and 150 mg — and the price per milligram is listed for each. The live table at the top of this page is read directly from the catalog, so the prices shown there are the prices in force today. See AHK-Cu in the catalog for availability.

What "50 mg" means on the label

The number is the net mass of AHK-Cu powder in the vial, as filled, and it is the quantity the certificate of analysis refers to. The vial is over-sized; the powder occupies only the bottom. That is normal for lyophilized material and is not a short fill.

Why the powder can look like a cake, a film or loose crystals

Freeze-drying leaves the peptide as a porous cake. During shipping the cake can break into a film on the glass or into loose blue-violet particles. The appearance does not change the quantity or the purity; only the COA does.

The COA is the document that turns a vial of blue powder into a defined reagent — and, for AHK-Cu, the document that proves it is not GHK-Cu under another label. A usable certificate carries:

• The laboratory's name and a verifiable identifier. Independent labs (Janoshik is the reference for this market) give each test a number that anyone can look up on the lab's site.
• The lot number — the same lot number that is printed on the vial you receive.
• HPLC purity as a measured percentage, with the chromatogram. "≥ 98 %" printed without a chromatogram is a claim, not a measurement.
• Mass confirmation by mass spectrometry: the observed mass matches AHK (about 354 Da for the free peptide), 14 Da above GHK.
• The date of the test. A certificate older than a few months describes a lot that has probably sold through.
• A photograph of the tested vial wearing the supplier's own label. A manufacturer's certificate showing a bare vial says nothing about what this supplier bottled.

The full checklist, with examples of what a doctored certificate looks like, is in how to read a peptide COA.

AHK-Cu is stable as a lyophilized powder when it is kept cold, dark and dry. The catalog's storage line for the sealed vial:

• Temperature: −20 °C for long-term storage; a refrigerator (2–8 °C) is acceptable for short periods.
• Light: keep the vial in its box or in an opaque container. The copper complex is light-sensitive.
• Moisture: the powder is hygroscopic. Let a cold vial reach room temperature before removing it from its bag, so no condensation forms on the glass.
• Shelf life: 24 months from the fill date for a sealed vial stored as above.

Shipping at ambient temperature for a few days does not degrade the sealed powder; that is why research peptides ship without cold packs. The general rules, size by size, are in lyophilized peptides: storage and shelf life.

"AHK-Cu" returns fewer sellers than GHK-Cu, and a larger share of them are cosmetic brands or resellers relabelling a manufacturer's lot. To sort them, ask six questions of the product page — not of the marketing.

1. Is there a batch COA from a named independent lab, and can it be verified on the lab's site? No verifiable COA = no purchase.
2. Does the COA show the supplier's own label? A manufacturer's certificate, re-used by a reseller, does not cover what was re-bottled or re-labeled.
3. Does the mass on the COA match AHK-Cu, not GHK-Cu? Same color, same look — only the spectrum separates them.
4. Does the supplier ship domestically, from US stock, in a few days? Long international transit is where vials get lost, heated or seized.
5. Does the page describe the product only — composition, purity, storage — with "research use only" stated plainly? A supplier that publishes usage content is a supplier that is easy to shut down; that risk transfers to any order in transit.
6. Is the price at or above the market, not far below it? Third-party testing costs several hundred dollars per lot. A price far under the market is a price that did not pay for testing.

The wider checklist — payment, packaging, what to do if a parcel is stopped — is in where to buy research peptides in the US. For the better-documented copper tripeptide, see the GHK-Cu buying guide.

The price of research AHK-Cu depends on the size of the vial, whether a third-party test was paid for the lot, and where it ships from. The catalog table at the top of this page shows the current price per vial and per milligram for each size.

What the price includes at OXpeptides: a sealed, labeled vial from a tested lot, the batch COA, tracked domestic shipping, and a replacement if a parcel arrives damaged. What it never includes: anything other than the reagent itself.

See AHK-Cu in the catalog →