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 Collagen Trois: Tretinoin + Copper + Estriol Trio UluRx 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 There is no definitive answer as to whether retinol vs peptides are better for anti aging. However, there is a lot more research backing retinol as an effective ingredient, while peptides are still