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The two are often believed to be interchangeable, but the main difference is that retinol is eventually converted into retinoic acid. Retinol is a natural form of vitamin A, while Retin-A is derived from retinoic acid, a synthetic derivative of vitamin A, and considered pharmaceutical.
Prescription Retin-A and Tretinoin and over the counter retinols increase skin cell turnover and stimulate collagen synthesis, explains Jennifer Chwalek, MD of Union Square Laser Dermatology. With consistent use of a topical retinol or retin-A you can see improvement of fine lines, dark spots, texture, and tone..