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 Wellness peptide craze: why people are injecting drugs 'not for human consumption' The Effect of the Human Peptide GHK on Gene Expression Relevant to Nervous System Function and Cognitive Decline Skin Restoration: Prioritizing Safety Over Trends