Question: what is the difference between retinoic acid and tretinoin?
Answer: Retinol and retinoic acid are related but distinctly different. Retinols first need to be converted by special enzymes into the active metabolite, retinoic acid. Only retinoic acid directly affects skin cells and helps reduce signs of aging. Tretinoin is a retinoic acid and does not need to go through this conversion.