GHK-Cu and AHK-Cu get mentioned together so often that it’s easy to assume they’re interchangeable. They’re close, but they aren’t the same molecule, and the evidence behind them is not equal.
One amino acid
Both are tripeptides, meaning three amino acids in a chain, and both carry a copper ion.
- GHK is glycine, histidine, lysine.
- AHK is alanine, histidine, lysine.
The only change is the first amino acid. Alanine is glycine with one extra methyl group, so AHK is very slightly bigger and very slightly more oil-loving. The histidine and lysine, including the part of the molecule that holds the copper, are identical.
Where they come from
GHK occurs naturally in the human body. It was found in blood plasma in 1973. AHK doesn’t. It’s an analogue, designed by changing one piece of GHK.
That matters mostly for how much is known. GHK-Cu has around fifty years of published research. AHK-Cu has a fraction of that, most of it laboratory studies.
What they’re sold for
GHK-Cu is mainly a skincare ingredient, used in creams and serums for skin that looks firmer and smoother.
AHK-Cu shows up mostly in hair and scalp cosmetics. It’s also added to skincare alongside GHK-Cu, on the reasoning that two related copper peptides cover more ground than one.
Neither is a medicine, and no honest seller will tell you either one treats anything.
On an ingredient list
| GHK-Cu | AHK-Cu | |
|---|---|---|
| Common name | Copper tripeptide-1 | Copper tripeptide-3 |
| Full listing | Copper Tripeptide-1 | Alanine/Histidine/Lysine Polypeptide Copper HCl |
| Colour | Blue | Blue |
Which to choose
If you want the better-understood ingredient, start with GHK-Cu on its own. It has the longer record and it costs less.
If you want both, look for a product that states the strength of each one separately. “Copper peptide complex” with no numbers tells you nothing about how much of either you’re getting.
Sine Cera makes both options, each as a cream and a serum: GHK-Cu at 1%, and GHK-Cu at 1% with AHK-Cu at 0.5%.
For more detail on each, see the GHK-Cu guide and the AHK-Cu guide.