GHK Cu: My secret weapon for skin, hair, and healing, I use it two ways topical cream for my face, and subQ injections 3x a week., It boosts collagen, tightens skin, helps hair grow, and even GHK Cu Copper Peptide: The Ultimate Peptide For Longevity Peptide side effects no one talks about BPC 157 headaches. TB 500 fatigue. CJC Ipamorelin water retention. Most people quit. But 90% of the time it's the protocol, not the peptide. GHK Cu Copper Peptides: Topical vs Injectable