Biotin supplement side effects: Is this vitamin harmful?

Biotin supplements help promote hair and nail growth. However, there are some side effects of biotin supplements you should know.

A man holding a glass of water in one hand and two pills in the other hand

Key takeaways

  • Biotin is readily excreted in the urine, making it difficult to suffer an overdose of this vitamin.
  • The body produces biotin in sufficient amounts in most people. However, people who have biotin deficiency can take biotin supplements to augment what their body produces.
  • Biotin supplements may interfere with specific test results, interact with other medications, and cause side effects like stomach cramps and insomnia. However, withdrawing the supplement can resolve these issues.

Biotin, also known as vitamin B7 or vitamin H, is one of the B-complex vitamins. It is present in foods like egg yolk, liver, milk, beef, carrots, and bananas. Biotin helps break down carbohydrates, fats, and proteins into fuel needed for the normal functioning of the body.

Biotin is usually produced in sufficient quantities by the normal flora present in the intestine. However, there are rare cases of inborn biotin deficiency in some individuals, which prevents their bodies from synthesizing biotin in the gut. When this happens, the individuals may experience hair loss, dry skin, and red rashes on the skin. Other causes of biotin deficiency include excessive alcohol intake, Crohn's disease, and certain medications.

Biotin is a water-soluble vitamin readily excreted in the urine, so you are unlikely to have excess amounts of biotin in your body. However, biotin supplements are now available in the market, and taking excess amounts may lead to mild side effects in rare cases.

Side effects of biotin

Biotin is generally safe when taken in proper amounts; however, studies show there are some side effects of taking biotin supplements. Here are the side effects of taking biotin you should know:  

1. Interference with tests

Biotin interferes with some test results, producing false positive or negative results. A review shows that biotin can interfere with thyroid function tests, leading to the misdiagnosis of hyperthyroidism. 

Another study shows that outside sources of biotin may interfere with tests that use the streptavidin (avidin)-biotin system. However, interference between biotin and these tests depends on several factors, like the dose of the biotin and the time between ingesting the biotin and taking the test sample.

2. Interaction with other medications

Biotin interacts with some medications like anticonvulsants, leading to a reduction in biotin levels. Drugs that interfere with biotin levels in the blood include phenobarbital, phenytoin, and carbamazepine.

When taking these medications, it is best to increase your biotin intake. Also, prolonged intake of antibiotics may destroy the gut bacteria responsible for synthesizing biotin. 

3. Ingesting too much biotin

In cases of biotin overdose, you may experience stomach upset and cramps. Biotin can also cause insomnia, acne, and skin rash when consumed in huge quantities.

Also, it is essential to know that biotin overdose is more common when an individual is taking biotin supplements. In most cases, withdrawal of the biotin supplement can cure these side effects.

Is biotin safe for everyone, including pregnant people?

When given in moderate amounts, biotin is safe for people, including pregnant people, and can help promote fetal growth. However, high doses of biotin can be harmful to the baby.

A safe dose of 30 mcg is recommended during pregnancy. 

Also, a study shows that pregnant people usually lack sufficient biotin; hence, supplementing is essential. However, it is best to get biotin from food sources instead of dietary supplements when pregnant.

What are the benefits of taking biotin?

Taking biotin from food sources or as a dietary supplement has several benefits. Four significant benefits of taking biotin include:

  • Promotes healthy nails 

Brittle nails are a common side effect of biotin deficiency. Taking biotin helps strengthen brittle nails and prevent breakage. 

A study shows that a dose of 2,500 mcg of biotin daily might improve nail hardness, firmness, and thickness, while a review also showed that biotin intake has promising results when used to treat various nail conditions. 

  • Supports hair growth

Biotin is a common component of hair products as it prevents hair loss and promotes its growth. However, a review suggests biotin is more effective in promoting hair growth in people already suffering from biotin deficiency. 

Another study also showed there may be a link between alopecia and biotin deficiency. 

  • Promotes healthy skin

Another common benefit of taking biotin is for healthy skin, as biotin deficiency is often associated with dermatitis. Several biotin supplements are marketed for this purpose, along with improving supporting hair growth and promoting healthy skin.

  • Regulate blood glucose

A scientific review showed that biotin may help reduce fasting blood glucose, total cholesterol, and triglycerides in people with type 2 diabetes mellitus. By reducing these factors, biotin helps manage type 2 diabetes. However, biotin does not have any effect on insulin. 

Also, a study in rats showed that supplementing biotin and chromium histidinate improves serum glucose and lipid levels.

Symptoms of biotin deficiency

An inherited condition known as biotinidase deficiency is the leading cause of biotin deficiency. Biotinidase deficiency is a rare condition in which the body cannot process biotin.

Excessive alcohol intake, pregnancy, and smoking may also cause biotin deficiency. Individuals with biotin deficiency may need to take biotin supplements.

Symptoms of biotin deficiency include:

  • Dry skin
  • Hair loss
  • Brittle hair
  • Dry eyes
  • Fatigue
  • Seizures
  • Insomnia
  • Nausea and vomiting
  • Stomach upset
  • Loss of appetite
  • Muscle weakness 
  • Red rashes on the skin
  • Cracking in the sides of the mouth

How much biotin should you take in a day?

The recommended dose of biotin for an adult is 30 mcg daily. However, lactating women can take up to 35 mcg daily.

Individuals with biotin deficiency are generally placed on a daily dose of 5 mg of biotin.

When is the best time to take biotin?

Biotin comes in various forms, like capsules, soft gels, and gummies, and is best taken in the morning so it doesn’t affect your sleep. Also, ensure you take a dose that is recommended by a healthcare professional.

Where to buy biotin supplements

You can buy biotin supplements over the counter in pharmacies and from trusted online marketplaces like Amazon and Jumia.

Wrap Up

Biotin is popular as a key ingredient in hair care products, although it has other benefits. Although rare, taking an overdose of biotin can cause severe side effects.

Always speak to a doctor if you are considering taking biotin supplements or if you have received a diagnosis of a medical condition that would require that you take biotin supplements.