PDF) Effects of GHK Cu on MMP and TIMP Expression, Collagen and Elastin Production, and Facial Wrinkle Parameters PSA] Albeit rare Copper peptide "uglies" are real and scary. Case report and looking for advices : r SkincareAddiction 12 weeks in, and my skin has NEVER looked better! GHK peptides are doing their thing. Alright, I need to give you an updateit's been 12 weeks since I started using GHK GHK CU Beverly Hills Rejuvenation Center