Biotin 101: Potential Benefits, Known Risks, and More

Biotin is a B vitamin that recently caught a lot of buzz as a nutrient that can thicken hair or improve the health of your nails. This is why you’ve probably seen it showing up in “beauty” supplements. But this vitamin is about far more than your looks — it’s vital for your overall health.

“Biotin is an essential water-soluble vitamin, also known as B7,” says Monique Richard, RDN, an integrative dietitian-nutritionist based in Johnson City, Tennessee, and a media spokesperson for the Academy of Nutrition and Dietetics.

Biotin plays a key role in your body’s metabolism. “Biotin is involved in the metabolism of fats, carbs, and proteins, meaning it’s needed to turn the food you eat into energy,” says Jillian Kubala, RD, the owner of Jillian Kubala Nutrition in Westhampton, New York. Your body doesn’t make biotin on its own, so you’ll need to get the nutrient from the foods you eat. In certain instances, you may also opt to take a supplement that contains biotin.

Vitamin B7 is naturally found in a variety of foods, such as whole eggs, canned salmon, pork, and hamburgers, and in smaller amounts in vegetarian sources like sunflower seeds, sweet potatoes, and almonds, per the National Institutes of Health Office of Dietary Supplements. One of the best sources of biotin is beef liver, which contains more than 100 percent of your daily need of the vitamin in just three cooked ounces.

As many as 29 percent of the nearly 38,000 adults in one study reported taking biotin from 1999 to 2012. Are you considering a supplement? Here’s how biotin may help you.

A Biotin Supplement Can Treat a Biotin Deficiency

One of the main reasons you’d reach for a biotin supplement is to reverse a biotin deficiency. Luckily, biotin deficiencies are rare, says Kubala, and according to the Office of Dietary Supplements, there has never been a severe biotin deficiency reported in healthy individuals eating a typical diet with a range of foods. “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. (U.S. newborns are screened for the condition, so if you were born in the United States, you’ll likely know if you have it.)

Separately, chronic alcohol use can affect biotin absorption, leading to a deficiency.

In addition, Richard points out that smokers are at risk for deficiency, and past research shows that smoking accelerates the breakdown of biotin in the body. 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’re concerned about your biotin levels.

Biotin Supplements Probably Do Not Improve Hair, Nail, and Skin Health

Google “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. The assumption is that extra biotin can lead to additional beauty benefits. What’s more, many of the hair and nail supplement products on store shelves include ingredients alongside biotin, such as collagen, zinc, and vitamin D.

The hype in this case may not be warranted: Claims that biotin improves the health of hair and nails are largely unfounded. “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 December 2020 review of oral hair growth supplements was blunt: “There is no evidence supporting the use of biotin as an oral supplement for hair growth.” 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, supplementing may indeed benefit your hair. One review found that biotin was useful in improving hair and nail growth in people who had an underlying disease associated with biotin deficiency. There’s been no proven benefit for healthy people.

When it comes to nail health, another review, published in the International Journal of Dermatology in August 2022, found that while biotin can treat brittle nails, it’s not effective for nail growth in general. Bottom line? There’s simply not enough evidence for dermatologists to recommend biotin supplements, according to an article in the April 2021 Journal of the American Academy of Dermatology.

Biotin Supplementation Is Helpful During Pregnancy and Breastfeeding

If you’re pregnant or breastfeeding, you may benefit from supplementation, says Richard. The recommended intake of biotin for adult women and men is 30 micrograms (mcg). 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 (as most do; read the label on yours). Also note that your biotin need increases to 35 mcg if you’re breastfeeding. You can continue to take your prenatal supplement throughout this period.

If you're interested in purchasing a biotin supplement, make sure you have the go-ahead from a healthcare provider first. “Before you buy a supplement for a specific reason, like thinning hair or brittle nails, it’s important to rule out potential underlying causes for your symptoms,” says Kubala. “There are a number of common medical conditions that can affect the health of the hair, nails, and skin, including hypothyroidism and iron-deficiency anemia,” she says.

If your healthcare provider has suggested a biotin supplement, here’s how to make a smart and safe purchase.

Selection

You can find biotin as a standalone supplement or in multivitamin and B-complex formulas. The benefit to B-complex formulas, says Kubala, is that they include other B vitamins that are more likely to be low in your diet, such as B12. “It makes more sense to take a multinutrient product than a biotin-only supplement,” she says.

Whatever brand you choose, double-check that the product is third-party tested, says Kubala. This ensures that what’s listed on the label, in terms of active and inactive ingredients, is in the bottle, and the supplement is free of contaminants.

Storage

Store biotin supplements in a cool, dark, and dry place. Bathrooms, the refrigerator, and your car are all places that can cause moisture to accumulate and degrade the supplement, according to iHerb.