What Is GHK-Cu (Copper Tripeptide-1)?
GHK-Cu is a copper-bound tripeptide (glycyl-histidyl-lysine complexed with copper) sold for laboratory research use only. Here is what it is and what to look for on a COA.
GHK-Cu (also called Copper Tripeptide-1, GHK-Copper, or Glycyl-Histidyl-Lysine Copper) is a small peptide complexed with copper. It is one of the most consistently competitive research peptides in the US vendor market on a per-milligram basis because larger vial sizes (50mg, 100mg, and bulk powders) drive the per-mg cost down significantly.
Structure and spec
GHK-Cu (copper tripeptide-1, CAS 89030-95-5) is the copper complex of GHK. GHK alone is about 340.4 g/mol; the 1:1 copper complex is about 402 to 404 g/mol depending on the form reported. The copper complex gives the powder its blue color.
Visual purity signal
GHK-Cu's blue color is itself a quality signal. A pale-blue, off-white, or fully-white powder indicates the copper complex is incomplete or absent. The COA's appearance field should describe the product as 'blue lyophilized powder.' Cross-reference the vial appearance against the COA on arrival.
What to look for in a GHK-Cu COA
Identity confirmed by mass spectrometry, with the reported mass matching the form stated on the certificate (about 340.4 for GHK, or about 402 to 404 for the copper complex), HPLC purity above 99 percent, named testing lab, and the appearance description matching the blue lyophilized powder spec. Endotoxin testing is less critical for GHK-Cu than for injectable GLP-1 family peptides given typical research applications.
Where to buy GHK-Cu
See our independent ranking of every US vendor carrying GHK-Cu, with per-milligram pricing comparison:
Frequently Asked Questions
Why is GHK-Cu blue?
The blue color comes from the copper-peptide complex. Pure GHK without copper is white or off-white. The blue color is a quick visual confirmation that the copper complex is properly formed.
Is GHK-Cu sold in larger sizes than other peptides?
Yes. GHK-Cu is commonly sold in 50mg, 100mg, and even 200mg vials, much larger than the typical 5mg or 10mg sizes for most peptides. Per-milligram pricing is therefore lower than for other compounds.
What is the difference between GHK and GHK-Cu?
GHK is the bare tripeptide (Glycyl-Histidyl-Lysine). GHK-Cu is GHK complexed with copper. They have different molecular weights and are distinct materials on a certificate.