Uses and Benefits #ghk GHK Cu is a naturally occurring peptide in human plasma that declines with age. When used in injections (usually subcutaneous), it can offer various benefits: Skin Rejuvenation and Anti Aging: Frontiers Exploring the beneficial effects of GHK Cu on an experimental model of colitis and the underlying mechanisms Amazon.com: GHK Cu Copper Peptide Supplement, Anti Aging & Hair Growth Support, Improves Skin Elasticity & Firmness, Thicker, Fuller Hair, Easy Absorption, Precisely Dosed, 90 Vegan Capsules : Health & Household Subcutaneous Injection Sites and Instructions for Safe Self Administration