Biotin is present in all living cells, and it plays a significant role in maintaining skin and hair health. As we age and our hormone levels fluctuate, the sebaceous glands in our skin and scalp start producing less sebum oil. This results in our skin, follicles and hair drying out and becoming flakey and brittle. Biotin can improve your skin and hair—and help offset these issues, among other benefits—by functioning as a growth factor and catalyst in carboxylation reactions.