6 Skin-Care Ingredient Combinations That Don't Mix Retinoid or Retinol and Alpha Hydroxy Acid. ... Retinoid or Retinol and Benzoyl Peroxide. ... Retinoid or Retinol and Vitamin C. ... Retinoid or Retinol and Salicylic Acid. ... Soap-Based Cleanser and Vitamin C. ... Two Products With the Same Actives. Jan 22, 2020