Copper Peptide Hair Growth Serum 10% GHK Cu & 5% AHK Cu Hairgenetix Copper Peptide Hair Growth Serum for Hair Loss & Thinning Hair Feline Skinscience Before and after begins with consistency. Our 10% GHK Cu formula is engineered for deep absorption to support scalp health and visible density. GHK Cu Copper Peptide: Dosage, Before and After Results, and How It Works Perfect B GHK Cu Peptide Progress: Week 3 Results