Are GHK Cu Injections Safe Enough? Alternatives Options Neurogan Health The Effect of the Human Peptide GHK on Gene Expression Relevant to Nervous System Function and Cognitive Decline Absence of evidence isnt evidence of absence its a popular argument, but its not how we should be guiding treatment decisions. In this short, I respond to a comment about GHK Cu injections for Amazon.com: Skin Perfection Copper Peptide Serum GHK CU 1% for Face & Hair Copper Peptides for Skin, Hair, & Scalp 1% Blue Liquid for Face, Neck, Body, Scalp Multi Use Serum Booster with