The Health Benefits of Biotin

A vitamin believed to stimulate hair growth and reverse hair loss

Biotin is an essential B vitamin that is used to promote hair health and growth. Because biotin deficiency can lead to thinning hair, proponents say biotin supplements can help correct this problem, though it may be a few months to see results.

Biotin is available in pill or tablet form. While biotin supplements may have benefits for some, there are also potential side effects that are worth considering before you start taking one. Using a biotin-containing hair product doesn't pose the same concerns, but claims they can thicken, strengthen, and add shine and volume to hair are not supported by science.

This article discusses the possible benefits of biotin for your hair and health. It also covers the potential side effects that may come with biotin supplement use.

biotin-rich foods

Verywell / JR Bee

Biotin Benefits

Biotin is an essential vitamin—meaning that your body needs this micronutrient to function properly. The biotin you consume in foods helps your body turn the food you eat (protein, carbohydrates, and fat) into energy.

Taking a biotin supplement is likely effective for treating biotin deficiency. However, some biotin supplements claim to have additional health benefits that are not supported by scientific evidence.


Click Play to Learn More About Biotin Hair Growth

This video has been medically reviewed by Casey Gallagher, MD.

Hair Growth

A handful of research studies have shown that biotin supplementation may help stimulate hair regrowth in people who have a clinical biotin deficiency or alopecia (hair loss). In people with temporary hair loss, studies have shown that supplements containing biotin significantly improved hair growth after 90 days.

That said, researchers also note that hair regrowth is often caused by many factors and may not be due to biotin supplementation at all. Furthermore, there is no evidence that biotin supplementation is beneficial for people who do not have an underlying condition causing their hair to thin.

Other Benefits

Other possible benefits of biotin include the treatment of:

Note, however, that there is insufficient scientific evidence confirming if biotin can treat any of these conditions.

Possible Biotin Side Effects

Biotin supplements can cause problems if you take too much. Side effects of biotin can include trouble sleeping, skin rashes, digestive upset, problems with insulin release, and kidney problems.

According to a report published in the New England Journal of Medicine, biotin treatment was said to interfere with laboratory tests and mimic Graves' disease—a condition that causes the thyroid to produce too much thyroid hormone.

As with any supplement, the safety of long-term or high-dose use isn't known. 

Dosage and Safety

The Food and Drug Administration (FDA) has not established a recommended dietary allowance (RDA) for biotin.

According to the National Institutes of Health (NIH), 30 micrograms (mcg) is the adequate daily intake for adults 19 years of age and older. People can usually get this amount through their diet.

Still, people who support its use often recommend taking 2 to 5 milligrams (mg) of biotin in supplement form daily in order to strengthen hair and achieve results.

Although biotin is a water-soluble vitamin (the excess is excreted in urine and feces), the safety of using any amount of biotin in supplement form is unknown.

As with many other supplements, biotin hasn't been tested for safety in pregnant women, nursing mothers, children, and those with medical conditions or who are taking medications.

Could You Have a Biotin Deficiency?

Biotin deficiency can occur in people who consume a lot of raw egg whites. That's because uncooked eggs contain avidin—a protein that blocks the absorption of biotin.

Since biotin is produced in the intestines, people with inflammatory bowel disease or other conditions that disrupt the balance of intestinal bacteria may not be able to produce enough biotin.

Excessive alcohol use, cirrhosis, and congenital biotin deficiency (biotinidase deficiency) may increase your need for biotin. A number of medications can lead to biotin deficiency as well. Among those are beta blockers, blood thinners, anticonvulsants, and retinoids.

If you notice any symptoms of biotin deficiency, consult your healthcare provider. Symptoms include:

  • Thinning of the hair
  • Brittle nails
  • Dry skin
  • A red, scaly rash (especially around the eyes, nose, and mouth) 
  • Conjunctivitis
  • Depression
  • Exhaustion
  • Hallucinations
  • Numbness and tingling of the arms and legs

Taking biotin supplements without being properly assessed by a healthcare provider poses the risk that diagnosis and treatment of the underlying cause of your symptoms will be delayed.

What to Look For

Biotin deficiency is believed to be uncommon.Bacteria in the intestines usually provides more than the body's daily requirements, and many foods contain biotin as well.

Biotin-Rich Foods

Food sources of biotin (in micrograms per 100 grams) include:

  • Cooked egg yolks (53)
  • Oats (27.0)
  • Wheat germ (17.0)
  • White mushrooms (16)
  • Spinach (6.9)
  • Cheese, brie (6.2)
  • Milk (3.5)
  • Pork (5.0)
  • Carrot (5.0)
  • Apple (4.5)
  • Tomato (4.0)
  • Beef (3.0)
  • Chicken (2.0)
  • Lettuce (1.9)


There are many reasons why your hair may be thinning or losing its volume, including infection, emotional or physical trauma, alopecia, and certain medications. There is not enough evidence to prove that biotin supplements are safe or effective. In most cases, the best way to prevent hair loss is to treat the underlying condition causing it.

A Word From Verywell

Unfortunately, you shouldn't believe everything you read on a product's packaging. While biotin has certainly become glamorized as a cure-all for hair health, manufacturers who shill biotin to promote their product aren't making factual claims.

Nevertheless, it is true that your hair can provide insight into your overall health and nutrition. If you are concerned about your hair health for any reason, talk to your healthcare provider. You may have an underlying condition, or perhaps, your diet simply needs a makeover.

Frequently Asked Questions

  • Does biotin help hair to grow faster?

    It depends. Research suggests that biotin can stimulate hair regrowth in people who have a clinical biotin deficiency. There is no evidence to show biotin can improve hair growth in people without nutritional deficiencies.

  • Can biotin cause a rash?

    Yes, applying a biotin product or taking a supplement can cause skin irritation and rashes in people who are sensitive to the B vitamin or other ingredients. Taking too much biotin can also cause a skin rash. People with sensitive skin should do a patch test on their inner arm before applying biotin to a larger area.

  • Does biotin cause weight gain?

    No, there is no evidence to suggest taking biotin supplements can lead to weight gain. In fact, biotin is sometimes touted as a weight-loss supplement. However, there is no research to support this use.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Ablon G. Clinical study a 3-month, randomized, double-blind, placebo-controlled study evaluating the ability of an extra-strength Marine protein supplement to promote hair growth and decrease shedding in women with self-perceived thinning hair. Dermatol Res Pract. 2015;2015:1-8 doi:10.1155/2015/841570

  2. Patel DP, Swink SM, Castelo-Soccio L. A review of the use of biotin for hair loss. Skin Appendage Disord. 2017;3(3):166-169. doi:10.1159/000462981

  3. Kummer S, Hermsen D, Distelmaier F. Biotin treatment mimicking Graves' disease. N Engl J Med. 2016;375(7):704-706. doi:10.1056/NEJMc1602096

  4. National Institutes of Health - Office of Dietary Supplements. Biotin.

  5. Réhault-Godbert S, Guyot N, Nys Y. The golden egg: Nutritional value, bioactivities, and emerging benefits for human healthNutrients. 2019;11(3):6. doi:10.3390/nu11030684

  6. Agrawal S, Agrawal A, Said HM. Biotin deficiency enhances the inflammatory response of human dendritic cellsAm J Physiol Cell Physiol. 2016;311(3):386-391. doi:10.1152/ajpcell.00141.2016

  7. Phillips TG, Slomiany WP, Allison R. Hair loss: Common causes and treatment. Am Fam Physician. 2017;96(6):371-378.

By Cathy Wong
Cathy Wong is a nutritionist and wellness expert. Her work is regularly featured in media such as First For Women, Woman's World, and Natural Health.