GHK-Cu (copper peptide): what it is, how it is supplied, and how to choose a research supplier

GHK-Cu is a small peptide of three amino acids — glycine, histidine and lysine (Gly-His-Lys) — bound to one copper(II) ion. The free tripeptide (GHK) has a molecular weight of about 340 Da; the copper complex is about 404 Da. It was first described by Loren Pickart in 1973 and is the most studied of the so-called copper peptides.

Two things make it easy to recognize on a laboratory bench:

• The color. The copper(II) ion gives the lyophilized powder a blue-to-violet tint. A white or gray "GHK-Cu" powder is either the copper-free tripeptide or something else entirely.
• The mass. On a certificate of analysis, mass spectrometry confirms the peptide at the expected molecular weight; the copper content is sometimes reported separately.

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

Searches for "GHK copper peptide", "GHK Cu", "GHK-Cu" and "copper tripeptide" all point to the same compound: the tripeptide GHK carrying one copper(II) ion. Suppliers and papers write it differently; the certificate of analysis settles it with the mass. Two labels do describe different objects:

• GHK (no copper) — the free tripeptide, a white powder of about 340 Da. Some listings sell this and call it "copper peptide"; the COA mass tells them apart.
• GHK-Cu — the copper complex, blue-violet, about 404 Da. This is what the catalog lists.

When a listing says "GHK copper peptide" without a mass on the COA, ask which of the two it is.

Most of what Google returns for "copper peptide" is cosmetics: serums and creams that contain GHK-Cu at a fraction of a percent, mixed with water, glycerin and preservatives. That is a different object from what a laboratory orders.

If a listing calls itself "GHK-Cu" but gives no mg quantity, no lot number and no COA, it is a cosmetic or a reseller — not a research supply.

Research GHK-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 — 100 mg, 200 mg and 300 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 GHK-Cu in the catalog for availability.

What "100 mg" means on the label

The number is the net mass of GHK-Cu powder in the vial, as filled, and it is the quantity the certificate of analysis refers to. The vial itself is over-sized (typically 3 mL for 100 mg): 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. For GHK-Cu, 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. A COA that cannot be looked up is a PDF, not a certificate.
• The lot number — the same lot number that is printed on the vial you receive.
• HPLC purity as a measured percentage (for example 99.2 %), with the chromatogram. "≥ 98 %" printed without a chromatogram is a claim, not a measurement.
• Mass confirmation by mass spectrometry: the observed mass matches GHK-Cu.
• 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 COA showing an unlabeled vial was issued to someone else — usually the manufacturer — and 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.

GHK-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.

"Buy GHK-Cu" returns a mix of cosmetic brands, clinics and research suppliers. 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. Is the quantity stated in mg, with a lot number on the vial?
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 becomes yours when your order is 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.

GHK-Cu vs AHK-Cu

AHK-Cu is the other copper tripeptide in the catalog (alanine instead of glycine at the N-terminus). It is supplied in smaller sizes (50, 100, 150 mg) and has a thinner literature. Both are described in the AHK-Cu buying guide.

The price of research GHK-Cu depends on three things: 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 GHK-Cu in the catalog →