Biotin, or vitamin H is part of the complex B vitamins. Along with helping the body metabolize fats and carbohydrates, biotin has been linked to improved hair health and maintaining proper function of the nervous system. Though it’s uncommon to have a deficiency in biotin, chronic smokers, alcoholics, pregnant women, those with Crohn’s and/or liver disease and anyone eating a diet loaded with processed foods are most likely to have a deficiency. Symptoms often reveal themselves through dry eyes, cracking on the sides of the mouth, scaly skin, depression and hair loss.

Biotin plays an important role in the growth and maintenance of your hair and nails. If you suffer from a Biotin deficiency, you will typically experience hair loss and brittle nails, and taking supplements of this vitamin may help to halt this process. In many cases, taking a Biotin supplement may even help you to stimulate new hair and nail growth. Even though hair loss is rarely caused by a Biotin deficiency in your body, this problem can quite often be helped if you take Biotin supplements regularly. Even if you have normal Biotin levels, you may choose to take Biotin as a supplement in the hopes of capitalizing on its ability to stimulate rapid hair and nail growth.

Though there’s minimal research to support the effects of biotin on hair growth, there’s strong evidence to support a deficiency will cause hair loss. Similarly, the vitamin also helps thicken nail cuticles and prevents breakage. A number of hair care companies are now including biotin directly in their products though doctors suggest taking biotin orally for optimal results.

Source(s): http://www.fitday.com/fitness-articles/nutrition/vitamins-minerals/the-benefits-of-biotin.html ,  http://www.chatelaine.com/health/wellness/biotin-can-boost-your-health/