New Biotinylated GHK and Related Copper(II) Complex: Antioxidant and Antiglycant Properties In Vitro against Neurodegenerative Disorders Diminishing Returns of Healthy Habits HaroldOster The Effect of the Human Peptide GHK on Gene Expression Relevant to Nervous System Function and Cognitive Decline Sherpa Performance Guides Diminishing Returns GHK Cu is the compound your body made at 25 and quietly stopped making. Most people find it in overpriced serums. Few understand what it actually does, or what happens when you're not