AHK Cu Copper Peptide Hair Growth Study (2007) Plain Language Summary Hairgenetix GHK Cu for hair growth does it actually work? Short answer: no. GHK Cu can be great for skin but when it comes to hair growth, the evidence just isn't there. And this Did you know your hair responds to peptides on a cellular level? Peptides like GHK Cu and AHK Cu don't just sit on the scalp, they send molecular signals that stimulate hair follicles, increase AHK CU Peptide Nationwide Peptides by National Science Labs, LLC