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What Is GHK-Cu? Copper Peptide Structure and CAS Numbers
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Testing Methods · 3 MIN READ · REFERENCE
01 / Overview
The peptide, the copper complex and their salts
GHK-Cu appears in catalogs under more than one CAS number, and the numbers are not interchangeable. Each identifies a different substance: the peptide alone, the peptide bound to copper, or a salt of either. The differences change the molecular weight, the appearance of the solid, and how much peptide a given weight contains.
The peptide
GHK is the tripeptide glycyl-L-histidyl-L-lysine, three residues with both ends unmodified. Its molecular formula is C14H24N6O4 and its molecular weight is 340.4. The CAS number for the free peptide is 49557-75-7. It contains no copper.
The copper complex
GHK binds copper(II), and the complex is the material usually meant by GHK-Cu. Its formula is C14H23CuN6O4, its molecular weight is 402.9 and its CAS number is 89030-95-5. The solid is blue, which is the visible signature of the bound copper. The names copper tripeptide-1 and prezatide copper refer to this complex.
Salt forms
The complex is also supplied as an acetate salt, listed under its own CAS number, 300801-03-0. A salt form adds the mass of the counterion, so the same stated weight contains less peptide.
Why the distinction matters
By weight, the copper complex is about 16 percent copper before any water or counterion is considered. A calculation that treats 50 mg of the complex as 50 mg of peptide is off by at least that margin. A listing that states the name GHK-Cu with the molecular weight or CAS number of the free peptide has described two different substances at once.
Telling them apart from the paperwork
Three items settle it. The CAS number states which substance is claimed. The molecular weight on the identity line should agree with that substance: near 340 for the peptide, near 403 for the complex. And the appearance line should agree as well, since a copper complex described as a white powder is a contradiction.
What FLASK lists
The material listed as GHK-Cu on this site is the copper complex, CAS 89030-95-5.
Frequently asked questions
Is GHK the same as GHK-Cu?
No. GHK is the free tripeptide at 340.4 Da; GHK-Cu is the copper complex at 402.9 Da, listed under a different CAS number.
Why is GHK-Cu blue?
The bound copper(II) gives the solid its color. A copper complex described as a white powder is a contradiction.
Which substance does FLASK list as GHK-Cu?
The copper complex, CAS 89030-95-5.
Key facts
- GHK peptide Gly-His-Lys, C14H24N6O4, 340.4 Da, CAS 49557-75-7, no copper
- GHK-Cu complex C14H23CuN6O4, 402.9 Da, CAS 89030-95-5, blue solid
- Acetate salt of the complex CAS 300801-03-0
- Copper share About 16 percent of the complex by weight
Related products & records
Read the specification and the record
Use the lot record and testing pages for the source analytical documentation.
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