Alternating tretinoin and GHK Cu (copper peptides) nightly maximizes anti aging benefits while minimizing irritation. , Both are potent but DIFFERENT actives. Tretinoin speeds up cell turnover and Copper Peptides vs. Retinol: Which Anti Aging Powerhouse is Right for Pure & Cimple GHK CU Crepey Skin Escape Did you know that Tretinoin can damage GHK Copper Peptides?. If you use Tret at night, save your GHK Lux for the morning. , Get the full safety guide on our YouTube Channel!, #platinum_skin_care