The GHK Cu pen works. But needles at home were never the answer. We took the same clinically backed copper peptide complex and put it into a serum you can use in 30 seconds, GHK Cu is the compound your body made at 25 and quietly stopped making. Most people find it in overpriced serums. Few understand what it actually does, or what happens when you're not Copper Tripeptide (GHK Cu) for Advanced Skincare & Haircare Formulatio Copper Peptides (GHK Cu): Benefits and Side Effects