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 Effects of GHK Cu on MMP and TIMP Expression, Collagen and Elastin Production, and Facial Wrinkle Parameters Copper Peptides (GHK Cu): Benefits and Side Effects Some people notice their skin looks worse before it improves with GHK Cu. This temporary phase is often called the copper uglies., #skincare, #ghkcu, #skinhealth, #longevity, #peptides