What Is GHK Cu? How It Works in Research and Quality Signals GHK Cu 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: The form of GHK Cu you use may matter more than the peptide itself. Which form of GHK Cu have you personally tried before and what was the FIRST noticeable change you experienced?