If you've researched products that support hair, nail or skin health, you may find it helpful that biotin is promoted as a dietary supplement. While biotin is marketed for these uses, it's actually an important vitamin that helps your body convert food into energy.

When it comes to taking biotin supplements, they are generally safe—especially if you stick to the recommended dosage. But like most things, too much biotin can be harmful.

What is biotin?

Biotin (vitamin B7) is a water-soluble vitamin. This means your body cannot store it, so excess biotin is excreted in your urine.

In most cases, people get enough biotin from their diet. Meats, nuts, and certain vegetables (such as sweet potatoes and spinach) are all sources of biotin.

Biotin is also available as an over-the-counter (OTC) dietary supplement when needed. It can be used alone, in combination with other B vitamins, or as part of a multivitamin. It is usually taken as an oral tablet in doses ranging from 10 mcg to 5,000 mcg.

What does biotin do?

Biotin is an important nutrient that supports many different processes in the body. But its main role is to produce energy from the carbohydrates, fats and proteins you eat every day.

Biotin is also recommended to support hair, nails, and skin health. But the evidence to support this is unclear.

What is a safe dose of biotin?

Everyone's situation is different. There are general guidelines for recommended amounts of biotin for each age group.

Some people may have difficulty getting the recommended daily amount of biotin. Therefore their provider may recommend a higher daily intake. People who may need large amounts of biotin include:

• smokes

• taking epilepsy medications such as carbamazepine or phenobarbital

• have an alcohol use disorder

• Are you pregnant or breastfeeding?

There is also a rare genetic disorder called biotinidase deficiency that affects how biotin is processed in the body. People with this disease need to take more biotin to ensure they are getting enough biotin.

Is it possible to overdose on biotin?

So far, there have been no reports of harm from taking too much biotin. Your body removes excess biotin through your urine because it is a water-soluble vitamin. However, side effects are still possible.

How to tell if you're taking too much biotin?

No maximum level of biotin has been established due to a lack of evidence that biotin is considered toxic (dangerous) at certain levels. In various studies, no side effects were reported when people took 10 mg of biotin by mouth daily.

Still, some people can develop symptoms if they take too much biotin. These symptoms include:

• stomach ache

• Insomnia

• excessive thirst

• Excessive urination

Are there other risks of taking biotin?

Yes. Large amounts of biotin can interfere with certain blood tests. Examples include:

• Troponin level: This is a blood test used to help diagnose heart strain and heart attacks. Biotin can cause false negatives for troponins. This means that the test results appear normal, but are actually abnormal.

• Hormone levels: Biotin can affect tests of thyroid hormones, reproductive hormones (called gonadotropins), and vitamin D.

These concerns prompted the FDA to issue a warning about biotin and laboratory testing.

What should I do if I accidentally take an overdose of biotin?

If you take a high dose of biotin or think you are experiencing side effects from taking too much, contact your healthcare provider for next steps. Most people recover naturally, but in more severe cases, supportive care may be needed.

What happens if you take too much biotin

For those of us wandering the vitamin aisle at our local drugstore, biotin is a staple. Thanks to some small studies it has been found to be a hero for healthy hair, nails and skin.
However, nutritionists and experts believe these aesthetic promises are overblown, noting that taking too much biotin may lead to misdiagnosis of other health problems.