Glutathione for the Skin Lightening : Benefits & Side Effects IV Drip GHK Cu Copper Peptide Serum with Hyaluronic Acid Anti Aging Facial Serum, Deep Moisturizing & Understanding Glutathione Deficiency Invigor Medical Defy GHK Cu (glycyl L histidyl L lysine) is a naturally occurring copper binding peptide found in human plasma. As levels decline with age, so may its support of the biological processes involved in collagen production, skin