Does biotin actually regrow hair? The bottom line. There’s no strong evidence to support using biotin for hair growth or to prevent hair loss in people without a deficiency. Because hair thinning and poor hair growth are sometimes associated with a biotin deficiency, correcting a deficiency can help restore hair growth in some people.
How much biotin should you take for hair growth? 2-5 milligrams
How long does it take biotin to work on hair? It takes months to see results on biotin. According to The Journal of Clinical and Aesthetic Dermatology (source), biotin takes around 90 days to begin to work. Contrary to some of the claims you may have heard, biotin is not an overnight remedy that will magically give you 5 inches of hair growth in 24 hours.