Here’s the research into whether biotin can help you.A Biotin Supplement Can Treat a Biotin DeficiencyOne of the main reasons you’d reach for a biotin supplement is to reverse a biotin deficiency, but biotin deficiencies are rare, says Kubala. “If you’re following a healthy, well-rounded diet, you’re probably taking in more than enough biotin on a daily basis,” adds Kubala.But a specific genetic disorder called biotinidase deficiency leads to biotin deficiency. (Doctors screen U.S. newborns for the condition. People born in the United States will likely know if you have it.)Separately, chronic alcohol use can affect biotin absorption, leading to a deficiency.[2]In addition, Richard points out that smokers are at risk for deficiency, and earlier research shows that smoking might accelerate the breakdown of biotin in the body in women.[4] Likewise, individuals with diabetes or malabsorption issues and people who receive tube feedings may be at risk for biotin deficiency. Talk to your doctor if you have concerns about your biotin levels.Biotin Supplements Probably Do Not Improve Hair, Nail, and Skin HealthGoogle “biotin supplement,” and you’ll be hit with a host of options, many of which are geared toward improving hair, nail, and skin health. Why? Hair loss, skin rashes, and brittle nails are all signs of biotin deficiency.[2] The assumption is that extra biotin can lead to additional beauty benefits. Moreover, many hair and nail supplement products on store shelves include ingredients alongside biotin, such as collagen, zinc, and vitamin D.Research doesn’t really support the unfounded hype in this case. “Unfortunately, there’s no evidence that biotin supplements improve the health or appearance of hair, nails, or skin unless you actually have a biotin deficiency, which is quite rare,” Kubala says. A review of oral hair growth supplements was blunt: “There is no evidence supporting the use of biotin as an oral supplement for hair growth.”[5] The authors also wrote that there’s no evidence that “biotin has a direct effect on hair follicle cycling or development.”That said, if you have a biotin deficiency, limited research found that supplementing it benefited hair. Another review found that biotin was useful in improving hair and nail growth in people who had an underlying disease associated with biotin deficiency.[6] That research was conducted on a small sample that mostly consisted of babies or children. There’s been no proven benefit for healthy people, and more research is necessary to confirm the hair benefits in people with biotin deficiency.A different review concluded that while biotin can treat brittle nails, it’s not generally effective for hair. Bottom line? There’s simply not enough evidence for dermatologists to recommend biotin supplements, according to a review of over-the-counter (OTC) supplements.[7]Biotin Supplementation Is Helpful During Pregnancy and BreastfeedingIf you’re pregnant or breastfeeding, however, you may benefit from supplementation, says Richard. The recommended intake of biotin for adult women and men is 30 micrograms (mcg).[2]That’s also the amount recommended during pregnancy, but it can be more difficult to get what you need during this time, which is why you may want to take a prenatal that includes biotin.[2] Also, note that your biotin needs increase to 35 mcg if you’re breastfeeding.[2]You can continue to take your prenatal supplement throughout this period — around 72 percent of prenatal supplements also contain biotin, according to a 2022 review.[8]