Growth hormone releasing hormone disruption extends lifespan and regulates response to caloric restriction in mice eLife Effects of Copper Tripeptide on the Growth and Expression of Growth Factors by Normal and Irradiated Fibroblasts Jeffrey D. Pollard, Susan Quan, Thomas Kang, R. James Koch, 2005 By age 30, your skin produces about 25% less collagen. By 40, that number can reach 40%. This decline affects more than just how your skin looks. It changes how it heals, Frontiers Exploring the beneficial effects of GHK Cu on an experimental model of colitis and the underlying mechanisms By age 30, your skin produces about 25% less collagen. By 40, that number can reach 40%. This decline affects more than just how your skin looks. It changes how it heals, Topically applied GHK as an anti wrinkle peptide: Advantages, problems and prospective