GHK-Cu is a coordination complex in which a copper(II) ion is bound by the tripeptide glycyl-L-histidyl-L-lysine (Gly-His-Lys). This profile documents its published identity, its metal binding, and its physical form as a research-use-only material, and makes no claims about biological activity or use.
Identity at a glance
GHK-Cu is a two-part identity: the peptide backbone and the metal it carries. Because the copper is part of what defines the material, the identity record needs to capture both. The fields below come from public chemical registries.
| Field | Value |
|---|---|
| Compound class | Copper tripeptide complex |
| CAS number (complex) | 89030-95-5 |
| Molecular formula | C14H22CuN6O4 |
| Molecular weight | 401.9 g/mol |
| Sequence | Gly-His-Lys, coordinating one Cu(II) ion (1:1) |
| INCI name | Copper tripeptide-1 |
| PubChem CID (complex) | 378611 |
| Free peptide GHK CAS | 49557-75-7 |
| Reported purity | 99.6% |
| Physical form | Blue lyophilized powder |
Sequence and copper coordination
The peptide part is short: three residues, glycine then histidine then lysine, running N-terminus to C-terminus. What sets GHK-Cu apart from a plain tripeptide is that it is described in the literature as a copper(II) complex, with the metal ion held by the peptide at roughly a one-to-one ratio. The histidine imidazole and the peptide backbone nitrogens provide the coordinating atoms typical of this class of copper-peptide chemistry.
Why the material is blue
The characteristic blue color of the solid is a direct consequence of the bound copper(II). Colored transition-metal complexes absorb part of the visible spectrum, and for many copper(II) species that absorption sits in the red to orange region, leaving a blue appearance. For identity purposes the color is a useful first-pass observation: a copper tripeptide preparation that arrives as a white powder is worth questioning against its certificate.
Two CAS numbers, one family
A frequent point of confusion is that GHK-Cu is associated with more than one registry number. The copper complex carries CAS 89030-95-5, while the free (uncomplexed) tripeptide glycyl-L-histidyl-L-lysine carries CAS 49557-75-7. They are related but not interchangeable: one includes the metal and one does not, and a certificate should make clear which material is in the vial. On the public structure side, the copper complex is recorded under PubChem CID 378611.
Physical form and laboratory handling
Advanced Sequence supplies GHK-Cu as a blue lyophilized powder in 50 mg and 100 mg sizes. As with other lyophilized peptides, the sealed powder is handled cold and dry and protected from light and moisture. This profile does not provide reconstitution amounts, concentrations per subject, schedules, or routes; those are outside the scope of an identity document. For the general chemistry of freeze-drying and rehydrating peptide solids, see the write-up on Sequence Notes.
You can review sample certificate fields on the lab results page and see packaged sizes on the GHK-Cu product listing. Certificate figures shown anywhere on the site are illustrative examples of the fields a real certificate of analysis carries, not a specific released lot the reader can purchase.
Reading the identifiers
Confirming a copper-peptide identity means checking the peptide sequence, the metal, and the salt or complex form together rather than trusting the name alone. The formula C14H22CuN6O4 encodes the copper explicitly, the INCI name Copper tripeptide-1 is the cosmetic-ingredient label for the same molecule, and the two CAS numbers separate the complex from the free peptide. Advanced Sequence positions this material strictly as a research-use-only reference compound, not as a cosmetic or consumer product.
Copper content as a separate specification
Because GHK-Cu is a metal complex, a complete specification treats the peptide and the copper as two things to confirm rather than one. A certificate for the complex commonly reports peptide purity by HPLC alongside a copper-content figure, since a preparation could in principle carry the correct peptide with too little or too much associated copper. Reading only the peptide purity, and ignoring the copper specification, would give an incomplete picture of a copper-tripeptide material.
Why the 1:1 ratio matters for identity
The complex is described with copper held by the peptide at roughly a one-to-one ratio. That stoichiometry, together with the two backbone protons the copper(II) ion displaces on binding, is what the molecular formula C14H22CuN6O4 encodes, which is why the copper appears explicitly in the formula rather than as an afterthought. When a document lists a copper tripeptide but leaves the metal out of the formula, that is a prompt to check whether the material in the vial is the complex or the uncomplexed peptide.
Confirming the material at receiving
A practical receiving check for a copper-tripeptide reference material runs through three observations that should agree with the certificate. The powder should be blue rather than white, which is the visible sign of bound copper(II). The stated CAS number should be the complex number, 89030-95-5, and not the free-peptide number, 49557-75-7. And the formula on the paperwork should include copper. Any one of these failing is reason to hold the material and question the document rather than to assume the name on the label is correct.
What this profile does not cover
As an identity document, this profile stops at structure, coordination, physical form, and the fields a certificate would carry. It makes no claim that GHK-Cu treats, improves, or affects any condition, body, or outcome, and it gives no preparation amounts, concentrations, schedules, or routes. The blue color, the copper specification, and the two CAS numbers are all identity facts; none of them is a statement about use.
Keeping identity and use strictly separate is the whole point of a profile like this. A researcher can rely on the copper specification, the color, and the registry numbers to confirm what arrived, and can look elsewhere, in the primary literature, for any question about what the compound has been studied in relation to.
Common questions
What is the difference between GHK and GHK-Cu?
GHK is the free tripeptide glycyl-L-histidyl-L-lysine, CAS 49557-75-7. GHK-Cu is the same peptide coordinated to a copper(II) ion, CAS 89030-95-5. A certificate should state which of the two is in the vial.
Why is GHK-Cu blue?
The blue color comes from the bound copper(II) ion. Copper(II) complexes absorb part of the visible spectrum, often in the red to orange region, which leaves a blue appearance. A white copper-tripeptide powder is worth questioning against its certificate.
What is the molecular formula of the GHK-Cu complex?
The copper complex is recorded with the molecular formula C14H22CuN6O4 and PubChem CID 378611. The formula includes the copper atom explicitly, which distinguishes the complex from the free GHK peptide.