All these ingredients starting with 'R' (Retinol, Retinoic Acid) basically do the same thing.
Yes and no. Prescription formulas contain retinoic acid, the magic ingredient that fights visible aging; nonprescription alternatives need to be converted into retinoic acid by the skin at the cellular level. "In off-the-shelf formulas, the ingredient called retinol is the only derivative of vitamin A worth using," says Dana Sachs, an associate professor of dermatology at the University of Michigan Medical School. "There's a lot of literature showing that while retinol is more gentle than retinoic acid, biochemically it does exactly the same thing — it may just take longer to see results." The same can't be said for the derivatives called pro-retinols (aka, retinyl palmitate, retinyl acetate, and retinyl linoleate), which are the most gentle — but weaker, too. Of the formulas shown here, Retin-A requires a prescription, but the others are available over the counter: Skinceuticals Retinol 0.5 contains retinol, while Murad Retinol Youth Renewal Night Cream has retinyl propionate, a less irritating form of vitamin A.