What is biotin and how does it work?

Biotin is a popular hair supplement but could it help prevent hair loss and keep your locks shiny and healthy?

product flatlay shot of biotin vitamin supplements
(Image credit: Getty Images)

Biotin is a supplement on a lot of people's radars when it comes to addressing hair loss and improving hair health. If having healthy, shiny hair is a goal, then it's worth knowing more about this popular vitamin. 

As hair loss can be unpleasant and frustrating for both men and women, many people often look for treatments to address this issue and also prevent it from happening in the first place. Many of these hair loss treatments contain biotin. What exactly is it and how effective is taking it in improving hair growth?

What is biotin?

Biotin is a B vitamin that is also called vitamin B7 or vitamin H. It's naturally found in certain foods, including liver, salmon, cheese, legumes, egg yolks, nuts, and sunflower seeds. It's water-soluble, so it doesn't get stored in the body. In addition to food sources, biotin can be taken as a pill or used as a topical treatment. It's been added to the best shampoos, hair serums, skin creams, and nail treatments.

Biotin benefits

Biotin has a multitude of health benefits, which can explain its popularity. According to Medical News Today, it helps in digestion, supports nail and hair health, improves skin, helps with pregnancy and breastfeeding, lowers blood sugar for people with diabetes, and may help multiple sclerosis treatment.

  • Improves digestion: Biotin helps out the enzymes that process fats, proteins, and carbohydrates in food and turns them into energy.
  • Supports nail and hair health: A biotin deficiency can cause brittle nails and hair loss.
  • Improves skin: People with a biotin deficiency sometimes have skin issues like a scaly rash. Biotin may also help improve psoriasis.
  • Helps with pregnancy and breastfeeding: A biotin deficiency is more common during pregnancy or breastfeeding, but medical tests should determine if supplements are needed.
  • May reduce blood sugar: Biotin may be helpful for people with type 2 diabetes, but more research is still needed.
  • May help multiple sclerosis treatment: There is also some research that suggests biotin supplements could help in the treatment of multiple sclerosis (MS).

A biotin deficiency is rare, but it is more likely for people who are pregnant or nursing, people who drink a lot of alcohol, or people who frequently eat raw eggs. Since people generally get biotin naturally in food, there's little evidence that taking extra is beneficial unless someone has a biotin deficiency.

Biotin side effects

Biotin is thought to be very safe even at higher levels since it doesn't get stored in the body. No side effects have been reported when taking up to 10,000 mcg (which is 10 mg) of biotin each day, according to the Mayo Clinic. However, biotin may cause unusual lab results, including thyroid test results, so people with a thyroid condition should consult a doctor before taking biotin.

It is possible for biotin to interact with some medications, according to the Office of Dietary Supplements at the National Institutes of Health. Other medications can affect a person's biotin levels. One type of medication to note is anticonvulsants used to treat epilepsy, which were found to lower biotin levels.

When to use biotin (and when not to)

While some people have been tested and do have a biotin deficiency, taking biotin is often the general advice for anyone with hair loss. Taking a biotin supplement sounds like an easy solution, but there isn't much evidence proving that it works. However, some people feel the anecdotal results are convincing enough to make it worth trying out biotin for themselves.

Unless a biotin deficiency has been diagnosed, there's little data that supplements containing biotin are helpful. "The take-home message is that these skin, hair and nail supplements are really not necessary from a health standpoint," Dr. Zoe Diana Draelos, president of Dermatology Consulting Services, PLLC., High Point, N.C., told Dermatology Times. "The nutrition you need can be obtained very easily with a multivitamin or, probably better, through adjusting your diet to include more fruits and vegetables."

Doctors can test for a Biotin deficiency, but they can also look for other underlying health conditions that could be causing hair loss. Reasons could include stress, hormone imbalances, vitamin deficiencies, extreme dieting, genetic conditions, autoimmune diseases, or even some hairstyles or color treatments.

How to use and apply biotin

According to the Office of Dietary Supplements at the National Institutes of Health, adults should get 30 mcg of biotin per day, and people who are nursing should get 35 mcg per day. Many supplement pills contain between 1,000 and 10,000 mcg of biotin in each pill. However, it likely isn't useful to take a biotin supplement unless medical tests have found a biotin deficiency.

Biotin can also be found in some shampoos and other products which can be used once or twice a week by most people, those with oily hair can use it more frequently. Some outlets, like The Chicago Tribune, have reported that biotin shampoos can help strengthen brittle hair.  However, other outlets, like Yahoo! News, that say there's no scientific evidence that this addition helps with hair loss. 

Biotin is a vitamin found in food that can be taken as a pill or used in topical forms. While important for a healthy body, biotin deficiencies are rare, except during pregnancy and breastfeeding. 

However, people hoping biotin will help reverse hair loss shouldn't experience adverse reactions to supplementing the biotin they already get from food.

Eunice Lucero-Lee
Eunice Lucero-Lee

Eunice Lucero-Lee is the Beauty Channel Editor for woman&home. A lifelong creative writer and beautyphile, she graduated from De La Salle University in 2002 and was hired a year later to front all beauty coverage for Pink Magazine, a teen lifestyle publication, after submitting a page-long thesis on why Stila was the best brand to come out of the Aughts. She was hired an hour later. 


Her writing—which has since then expanded to cover pop culture and astrology, both equal passions—led her to spearheading columns in Chalk Magazine, K-Mag, Metro Working Mom, and SugarSugar Magazine. Upon receiving her stripes at New York University’s Summer Publishing Institute in 2008 she was immediately headhunted to work as the Beauty Editor, thereafter Managing Editor of Stylebible.ph, the digital home of Preview, the Philippines’ best-selling fashion magazine, where she also did double-duty as Associate Editor of the print edition.


It was during this stint that the hallyu wave started taking hold and when she was tapped to co-found Sparkling, Asia’s first-ever English K-Pop print magazine. Originally planned as a one-off, the project became a runaway hit and saw her taking Korean classes on the weekends for three years, as she found herself frustrated by the lack of breadth translators provided for celebrity profile coverage. She was Editor-in-Chief until her move to New York in 2013. The now-iconic magazine has remained in publication since 2009 due to massive fan support.


A beauty, astrology, and pop culture obsessive and insider for over 18 years, Eunice is an internationally published editor (and now certified astrologer) whose work has been featured in publications such as Cosmopolitan, Esquire, and The Numinous, among many others. The former Editor-in-Chief of All Things Hair and a (very) proud cat mom, she spends her time in Manhattan figuring out the correct Pilates-to-sushi ratio, obsessing over celebrity natal charts, luxury skincare, and Scandi-noir crime procedurals, as well as finding the perfect K-Pop vid to save the day. She can still order drinks perfectly in Korean. Find her on Instagram @eunichiban.