Everything You Need to Know About Biotin

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Biotin is often listed as a key ingredient on everything from shampoos to styling products, and supplements for hair, skin and nails are more popular than ever before—some gummies are so delicious, they make for an easy swap for an afternoon sweets craving instead of candy (which I used to opt for!). However, not everyone needs biotin, so we’ve spoken to three top dermatologists to get the scoop on everything one should know about this in-demand booster for hair, skin and nails.

What is biotin?

Also known as vitamin B7, “biotin is one of the B complex vitamins found naturally in a variety of foods we eat such as eggs, fish, meat, nuts, seeds, and dairy products—we also produce it naturally from our intestinal bacteria,” says Beverly Hills, CA dermatologist Ava Shamban, MD. “B vitamins are key for keeping our nervous system healthy, they’re vital nutrients for embryonic growth in pregnant women, and they help keep our skin, hair, eyes, and even liver functioning healthy. Biotin is also involved in a wide-ranging list of metabolic functions, including processing of glucose, fats and proteins in our cells. It helps convert energy for the cells in our body and plays a key role in the building blocks of healthy skin.” Delray Beach, FL dermatologist Dr. Janet Allenby adds that biotin levels can be depleted in the body if you have kidney disease, malabsorption disease or you’re taking certain medications. 

What are the benefits?

If someone is deficient in biotin, they may see dry, brittle nails, split ends and hair breakage, as well as more sallow dull skin. According to Dr. Shamban, biotin helps the formation of the fatty acids that create the elasticity, strength and density for hair, nails and skin. “It is often referred to as ‘hair food,’ and is popular for hair growth and nail strength,” she says, noting that there isn’t much scientific evidence supporting this. “Most of us are not actually deficient in vitamin B, but adding it into our diet does seem to improve hair and nail strength growth and moisture levels for skin. With enough biotin-rich, protein-filled food in our diet, properly broken down by enzymes, the biotin is ‘freed’ and can get to work.” Biotin can also be used in treatments for diabetes and nerve problems.

How does it differ when used topically versus ingested?

Biotin is listed as a key ingredient in many hair-care products, including shampoos, conditioners, masks, serums, and even stylers. Rochester, NY dermatologist Lesley Loss, MD says that when used topically, biotin will not make hair grow faster or longer, but it may promote longer, stronger hair by strengthening the hair follicle with consistent use. “Keep in mind: Scientific evidence suggests that unless a person is biotin-deficient, ingesting biotin or implementing a biotin-based topical regimen will not make much of a difference.”

Dr. Allenby says biotin is best utilized as an oral supplement, which she uses in her aesthetic dermatology practice. “I like Skinade and Nutrafol oral supplements that are used to improve skin, hair and nail health and growth,” she notes. “We commonly use them if a patient has hair loss or has lost the luster in their skin and hair.”

Are there any ingredients you shouldn’t mix with biotin, or any side effects?

Though generally considered safe and drug interactions are rare, some skin rashes and digestive issues can occur after beginning supplementation over using a new topical product. However, Dr. Loss notes that mixing biotin with some medications can be harmful and cause potential side effects. “If you take other medications or supplements, talk to your board-certified dermatologist or general practitioner before adding biotin to your supplement regimen,” she explains. “It’s important to note that hair and nail issues can sometimes reflect deficiencies in other things, like iron, vitamin D or low thyroid. If you are considering a biotin regimen to treat hair and nail issues, definitely talk to your dermatologist or doctor to properly evaluate and diagnose your issue. Biotin can also alter thyroid function tests, so having these discussions prior to starting a biotin regimen is preferred.”

Other potential side effects, Dr. Shamban notes, include a potential effect on lowering blood sugars, which can be important for those with diabetes to be aware of and monitor.

What are the best ways to use biotin?

If you’re using topical products, it’s best to patch-test areas first to make sure your skin is compatible with the formula. For those who prefer the supplement route, Dr. Shamban says additional biotin supplementation is usually not necessary with a balanced diet. “National Institutes of Health reporting concurs there is insufficient data to support most recommendations or need for supplementation, and much of the noted improvements are more anecdotal and not clinically supported with significant research for end points on these claims in healthy individuals. That said, many of my patients feel they experience improvements. So, for those who find it beneficial to the appearance of their hair, skin or nails, it is safe and generally well-tolerated for ongoing usage.”

If you’re part of the biotin fan club, it’s important to know that the vitamin can have harmful side effects if too much is ingested. “I recommend no more than 10 milligrams daily in supplement form, and generally steer my patients to a more moderate 2-5 milligram daily limit when they are taking biotin for cosmetic purposes,” says Dr. Loss. And because biotin is a water-soluble vitamin, any excess will pass through the body and be excreted naturally.

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