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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.
Retin-A vs. Retin-A Micro Differences. Retin-A and Retin-A Micro are basically different versions of the same medication. They work in the same way, they're used to treat the same skin problems, and they contain the same active ingredient. The main difference between Retin-A Micro and Retin-A is how they are formulated.