Why You Shouldnt Mix GHK Cu with AHA, BHA, or Retinol, If youre using a GHK Cu (Copper Peptide) in your skincare routine, layering it with strong actives like AHA, BHA, or retinol may actually CLEARED Copper Peptide Skin Care Cream 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 Frontiers Exploring the beneficial effects of GHK Cu on an experimental model of colitis and the underlying mechanisms