What Is Biotin Good For, Exactly?

The B vitamin does so much more behind the scenes than you may realize.

Brittle nails, fraying split ends, dull skin: These cosmetic details may encourage you to ask your doctor about starting a biotin supplement. But what exactly is biotin, and apart from potentially making your hair glossier, has science indicated it provides other health benefits?

Biotin, also known as B7, is a water-soluble vitamin, meaning your body does not store significant quantities of it. So, if you were to take a biotin supplement that exceeded your body’s needs, you’d probably excrete the remainder through urine. “Our bodies do not produce biotin directly, but bacteria in our digestive system do synthesize it,” says board-certified dermatologist and dermatologic surgeon Tyler O. Vukmer, D.O.

The authors of a 2023 study on biotin deficiency and intestinal dysbiosis explain that microbiota (AKA bacteria) in the gut “depend on biotin for growth and survival.” In other words, gut bacteria (primarily located in the large intestine) create biotin out of necessity on its own.

But, for some people, getting additional biotin via foods and supplements may help boost certain aspects of their health.

Benefits of Biotin

If you’ve been wondering what biotin is good for, you may be surprised to learn that it does so much more than strengthen your nails (although that’s important, too!).

Supports metabolism

B vitamins of all kinds help the body convert carbs into energy, but biotin plays a specific role in metabolic functioning. “Biotin is necessary for the functioning of a group of (biotin-dependent) enzymes, known as carboxylases, which are active in metabolism and energy production,” explains dietitian nutritionist Vanessa King, M.S., R.D.N.

Without biotin, you wouldn’t properly metabolize the core macronutrients found in food (carbs, protein, fat), which are vital to your brain and body. (Note: You likely get enough biotin through your gut microbiota and the foods you enjoy, so a supplement isn’t necessary for healthy metabolism.)

May help with Diabetes management

When you think of interventions that keep your blood glucose and cholesterol levels in check, a biotin supplement probably isn’t the first thing that comes to mind. However, in those who have type 2 diabetes, biotin supplementation may help to improve both of these biomarkers.

Megan Huff, RD, a clinical dietitian at Piedmont Healthcare in Atlanta, points to a 2022 systematic review of five randomized controlled trials. The findings reveal that taking biotin for 29 to 90 days helped decrease total cholesterol, triglycerides, and fasting blood glucose levels in those with type 2 diabetes. Of course, lifestyle changes such as watching carbohydrate intake and engaging in regular physical activity are the best ways to manage type 2 diabetes.

Promotes a healthy pregnancy

According to the National Institutes of Health (NIH), as many as one-third of pregnant women develop a slight biotin deficiency—even when their intake of the vitamin is considered normal. “Some pregnant women may have increased needs for biotin as it supports the growth of the fetus,” says Huff.

For this reason, biotin is one of the many vitamins that can be found in a prenatal multivitamin, with recent research indicating it’s found in 72% of prenatal supplements in the U.S. And for a good reason—biotin deficiency could be a cause for preterm delivery, suggests a small-scale 2020 case-control study.

May improve hair, skin, and nail health

If you already have healthy biotin levels, taking a supplement will not make your hair shinier, your skin dewier, or your nails un-chippable. However, according to a review from a 2017 issue of the journal Skin Appendage Disorders, a biotin supplement can help improve skin, nails, and hair in those deficient in biotin. (Remember, it’s rare to be deficient in this B vitamin.)

Still, it’s not a myth that biotin can support your hair, nails, or skin in its current state. Vukmer points out that biotin is necessary for keratin production, an important protein that forms your hair, nails, and skin.

Is Biotin *Actually* Good For Hair Growth?

The answer to this is similar to the above: Biotin usually only supports hair growth if you have a biotin deficiency. And the B vitamin can be incredibly helpful for those who don’t have sufficient stores of it. One 2016 study found that 38% of women who experienced hair loss had biotin deficiency. The study authors suggest taking 5 mg of biotin daily via a supplement may help restore lost strands.

Sources of Biotin

You can reap the benefits of biotin from a range of different sources—from nutrient-dense foods to expert-backed supplements.

Foods

According to the NIH, the following foods are rich in biotin:

Several other plant-based foods, such as spinach, broccoli, and oatmeal, offer 2% or less of the daily value of biotin per serving.

Supplements

Another way to increase your biotin intake is to take a dietary supplement, such as a pill or capsule. Supplements containing biotin only, as well as multivitamins and mineral products, are available.

Vukmer recommends looking for supplement brands with third-party certification, as the FDA doesn't regulate supplements. “Third-party certification means that these organizations have tested and attest to the fact that the label accurately describes the product,” he says.

Is a Biotin Deficiency Common?

Biotin deficiency is rare, but there are a few exceptions. Chronically abusing alcohol can prevent biotin absorption. People who are pregnant or breastfeeding may also be at higher risk of a slight biotin deficiency. However, a true biotin deficiency is unlikely in those who consume healthy diets.

Deficiency symptoms typically manifest as a skin rash or a peeling rash on the face, thinning hair, hair loss, and brittle nails. Remember that just because you exhibit one (or a few) of these symptoms doesn’t mean you have biotin deficiency. Many of these symptoms overlap with other health conditions, so speak with a healthcare provider if you have concerns.

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