Biotin For Hair Growth: Does It Work?

Biotin can support hair growth in people whose hair is thinning or falling out due to a biotin deficiency. Other vitamin deficiencies can also affect the health of your hair.

When I shop at a chain store, I like to browse their nutritional supplement offerings to keep up to date with new products.

I’ve noticed more and more products that offer targeted health solutions, especially around hair growth and thickness.

Most products contain multiple ingredients. Biotin, a water-soluble B vitamin, is almost always one of them.

Likewise, many shampoos and conditioners that promise thicker, fuller hair often contain this B vitamin.

The recurring theme here is that biotin, whether taken as a supplement or lathered into your hair, supposedly benefits hair growth.

This article explains the link between biotin and hair health and whether the vitamin is effective and safe for hair growth or preventing hair loss.

Biotin has many benefits for your body.

Its primary role is to help convert the food you eat into energy. Your body also needs it to produce keratin — the type of protein that makes up hair, skin, and nails (1).

Many foods contain biotin, meaning deficiency is rare in healthy people who eat a balanced diet (2).

Although rare, a biotin deficiency can cause skin rashes, brittle nails, and thinning and falling hair. This is due to the vitamin’s role in the production of keratin (2, 3).

As such, biotin supplements and hair products containing biotin are often advertised to support healthy hair growth or promote thicker, voluminous hair.

Despite these claims, however, there is limited evidence to suggest that supplementing with biotin or lathering it through your hair promotes hair growth in people without deficiency.

In an older 2012 study, women with self-perceived thinning hair were randomized to receive either a multi-ingredient hair growth supplement containing biotin or a placebo for 6 months (4).

Those who received the hair growth supplement reported a visible increase in total hair volume, scalp coverage and thickness after the treatment period. Meanwhile, no significant changes were seen in the placebo group.

However, because the hair growth supplement contained multiple ingredients, including zinc and iron, which are also necessary for hair growth, it is not possible to attribute the study’s findings to biotin alone.

Furthermore, the study was small and it is possible that the participants were deficient in one or more nutrients in the supplement that affect hair health. Such a deficiency could have been corrected during the study period, resulting in hair growth.

In another study, researchers found that children who experienced improved hair growth or quality after taking biotin supplements all had an underlying condition that caused a biotin deficiency (3).

Outside of these studies, there is no strong evidence to support the use of biotin supplements or the use of hair products with added biotin to promote hair growth (2).


A biotin supplement can help correct a biotin deficiency and restore hair health and growth. There is no strong evidence to support the use of biotin supplements or hair products containing biotin to promote hair growth in non-deficient people.

While the evidence to support biotin alone for hair growth is weak and limited, the evidence is slightly stronger for preventing hair loss.

Still, biotin supplements are likely only to prevent hair loss and promote hair growth in people with a biotin deficiency.

In one study, biotin deficiency was found in 38% of women who complained of hair loss. Of these participants, 11% had a history of risk factors for deficiency, such as inflammatory bowel disease (IBD) or the use of certain medications such as antibiotics (5).

While this study did not assess the effects of biotin supplements or hair products containing biotin on preventing hair loss, it does demonstrate the link between hair loss and inadequate biotin levels.

Other causes of hair loss are (5, 6):

  • androgenetic alopecia, also known as female pattern baldness
  • fast weight loss
  • other nutritional deficiencies such as iron, zinc or protein
  • certain hormonal diseases such as thyroid disease

Due to the many factors involved in hair loss and thinning hair, biotin supplementation without determining the cause may prevent or delay proper treatment in cases where a biotin deficiency is not to blame.

Even in cases where a biotin deficiency is present, biotin supplements do not necessarily prevent hair loss.

For example, researchers in one study prescribed a biotin supplement to 22 patients with low biotin levels for hair loss after gastric sleeve surgery (6).

After 3 months, 5 of the patients reported a significant decrease in hair loss, 14 reported a small effect and 3 reported no effect, showing that other factors may also play a role when it comes to hair loss and its prevention.


Because hair loss is sometimes associated with a biotin deficiency, correcting a deficiency with supplements may prevent hair loss in some people. However, hair loss can also be a result of several other factors.

Normally, the Food and Nutrition Board of the National Academies of the Sciences, Engineering, and Medicine sets a recommended dietary allowance (RDA) for each nutrient.

When there isn’t enough data to set an RDA for a nutrient, which is the case with biotin, the board instead sets an adequate intake (AI). This is the nutritional level considered adequate for most people (7).

The AI ​​for biotin is 30 mcg for adults and 35 mcg for breastfeeding women (2).

You can easily meet these recommendations by enjoying a balanced diet. In fact, it is estimated that people living in the United States consume about 35-70 mcg of biotin per day (2).

Here are some of the best sources of biotin (2):

Eggs are a good source of biotin, but avoid consuming them raw to get the most out of the vitamin. Raw egg whites contain avidin, a type of sugar protein, that binds biotin tightly, preventing your body from absorbing it.

Cooking destroys avidin, allowing you to absorb biotin. So it’s best — for both your safety and your nutrition — to avoid raw eggs (2).

The Food and Drug Administration (FDA) does not require food manufacturers to list biotin on their labels unless they add it to their products.

In addition to food, the bacteria in your gut can make biotin. However, the role of gut bacteria on the overall biotin status of humans remains unknown – in part due to the complexity of the gut microbiota and the factors that influence its composition (8).


People in the United States generally meet or exceed the daily biotin recommendation. Animal foods such as eggs, meat and fish are usually the best source, but some seeds, nuts and vegetables also contain it.

Biotin supplements are generally not necessary unless you have a biotin deficiency or a risk factor that increases your risk of deficiency.

People most at risk for a biotin deficiency are those with (2, 9):

  • Biotinidase deficiency (BTD). A genetic condition in which the body cannot reuse and recycle biotin. Newborns in the United States and many other countries are screened for this condition.
  • Chronic alcohol use. Because alcohol inhibits biotin absorption, long-term alcohol consumption is associated with significant reductions in biotin levels.
  • Malnutrition. Inadequate intake of food and nutrients can lead to low levels of nutrients, including biotin.
  • Inflammatory bowel disease (IBDs). Crohn’s disease and ulcerative colitis can reduce the production of biotin by the gut bacteria.

Those who are pregnant and breastfeeding may also develop low levels of biotin despite normal dietary intake of the vitamin. This may be due to increased use of the vitamin, decreased absorption, or both (10).

People taking certain types of medications, such as anticonvulsants and retinoids, are also at risk for a biotin deficiency (9).

Antiepileptic drugs are commonly used to treat convulsions, nerve pain, and bipolar disorder. Retinoids are a class of compounds derived from vitamin A that are commonly used to treat acne, psoriasis and other dermatological conditions (11).

Outside of these populations, biotin supplements or hair products containing biotin are unlikely to provide benefits (12).


People at risk for biotin deficiency include those with BTD, chronic alcohol use, malnutrition, and IBD. Those who are pregnant and breastfeeding, as well as those taking certain medications, are also at increased risk.

Biotin taken as a dietary supplement is relatively safe and unlikely to have any toxic effects because it is water soluble (1).

However, a biotin overdose can cause insomnia, excessive thirst and urination (13).

Its use can also lead to high levels of biotin in your blood, which can interfere with certain lab tests, including those used to measure thyroid hormones, vitamin D and heart health (2).

That’s because many lab tests use biotin for its ability to bind to specific proteins and detect certain health conditions (14).

Therefore, always let your doctor know about any supplements you are taking or plan to take that contain biotin. These may include some prenatal and multivitamins.

It’s also worth noting that some anticonvulsants — such as carbamazepine, primidone, phenytoin, and phenobarbital — can lower biotin levels.

If you’re taking any of these, talk to your doctor or a dietitian to make sure you’re getting enough biotin, through your diet, with a supplement, or a combination.


Biotin supplements are generally safe to take, but they may interfere with certain lab results. So keep your healthcare provider informed about any supplements that may contain this vitamin.

There is no strong evidence to support the use of biotin for hair growth or to prevent hair loss in people without a deficiency.

Because thinning hair and poor hair growth are sometimes associated with a biotin deficiency, correcting a deficiency may help restore hair growth in some people.

Several other factors can also cause hair loss and thinning hair, including a deficiency in other nutrients such as iron and zinc.

Most people get a lot of biotin through their diet. Still, some conditions, lifestyle habits, and medications can cause low levels.

If you plan to take a biotin supplement, let your doctor know before getting any blood work done, as the vitamin may interfere with some lab test results.

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Biotin For Hair Growth: Does It Work?

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