8 Potential side effects to know before taking biotin supplements

Vitamin H, commonly known as biotin, is a member of the vitamin B complex that helps convert carbohydrates and lipids into fuel. Healthy individuals produce normal amounts of biotin in the body through the gut’s microorganisms and by sourcing this vitamin from food. 

Some benefits of biotin include having healthy hair and nails, increased hair growth for biotin-deficient, healthy skin, and protection against cardiovascular diseases and type 2 diabetes. 

Food sources of biotin include beef, egg yolks, pork, milk, white mushrooms, cheese, lettuce, carrots, apple, spinach and oats. 

The functions of B vitamins include the following: 

  • Proper functioning of the nervous system and the brain 
  • Promote healthy skin, eyes, hair and liver
  • Normal growth of the fetus during pregnancy 

Biotin is a water-soluble vitamin, and any excess biotin from our food is excreted through the urine. Hence, it is rare to have biotin toxicity due to excess consumption of food sources rich in biotin

Adequate intake (AI) for biotin is 30 micrograms per day [1]. People with biotin deficiency include those with inherited genetic disorders that prevent them from using biotin correctly or from producing this vitamin in the body.

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Some biotin-deficient people also have medical conditions that prevent the adequate uptake of biotin in the body. For example, people with Crohn’s disease struggle to absorb nutrients from the small intestine.

Individuals with biotin deficiency due to medical conditions or genetic factors can receive biotin supplementation to address the shortage. 

8 side effects of biotin supplements

However, for some, taking biotin supplementation results in side effects. Here are seven potential side effects to be aware of when you are taking biotin supplements: 

8 side effects of biotin supplements

1. Digestive upset 

Taking biotin may lead to stomach upset, such as cramping, stomach troubles and nausea [2]. Whenever you experience any problems related to stomach upset, immediately talk to your doctor, who will assess if you are taking the adequate amount or if you need to stop taking biotin supplements. Your doctor may advise you to get biotin naturally from food rich in biotin if biotin supplementation results in constant stomach upset. 

2. Acne 

Acne is recognized as a common skin condition that occurs when hair follicles are clogged. Oil and dead skin cells clog these follicles, leading to pimples or lesions outbreaks. Bacterial infection can aggravate these pimples, leading to acne. 

Initially, biotin supplementation at 10mg daily can help maintain skin hydration in patients treated with isotretinoin [3]. Another study [4] that examined the effectiveness of biotin supplementation in treating acne showed that 12-week treatment with biotin reduced acne. Both studies contradict that excessive biotin supplementation can increase or trigger acne outbreaks. 

However, there are reports that excessive biotin supplementation can reduce the absorption of nutrients and vitamins that prevent acne development. Hence, in some cases, high-dose biotin supplementation may suppress other vitamins from protecting the skin against acne. 

3. Insomnia 

Insomnia, or the inability to sleep, is a common disorder that can lead to serious illness when left untreated. There are reports that excessive biotin supplementation can lead to insomnia.

Since biotin supplements are needed to metabolize fats and carbohydrates and turn these into energy, excessive intake of biotin during nighttime might lead to a surge of energy. This surge of energy may make it difficult for you to sleep. Hence, taking biotin early in the morning might help prevent insomnia or trouble sleeping. 

4. May interfere with results of thyroid function test 

Another known side effect of biotin intake is interference with laboratory test results, especially thyroid function tests. 

A case study [5] published in the Cureus journal examined four patients who were erroneously diagnosed with hyperthyroidism during a routine thyroid function test. Interestingly, none of these patients had hyperthyroidism when biotin supplementation was withdrawn.

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All patients in the case study were given 20-30 mg of biotin at the time of the thyroid function test. Before the biotin supplementation, all four patients were free from hyperthyroidism. 

The thyroid hormone values all returned to normal levels within 24-48 hours after withdrawal of biotin supplementation.

The findings of this study showed that it is essential to examine if patients are taking biotin supplements during thyroid function tests since results may be skewed. Further, skewed results can lead to inappropriate treatment and potential adverse effects from thyroid treatment. 

5. Skin rashes 

Biotin supplementation has been touted to improve skin texture, hair and nails. However, some people can experience side effects such as skin rash following biotin intake. Skin rashes are rare in those who take biotin.

These rashes could be due to an allergic reaction to biotin, with the immune system labeling biotin supplements as foreign to the body. Hence, it is essential to consult your doctor before taking biotin supplements, especially if you have a history of allergic reactions to other B vitamin supplements. 

skin rashes
Phtoograph: jeannierv/Envato

6. Interaction with other drugs 

Like other B vitamins, biotin can interact with other medications you might be taking. Hence, it is essential to talk to your doctor if you are currently taking drugs that have broken down and changed the liver.

For instance, biotin may interfere with the breakdown of certain medications in the liver. Biotin might increase or decrease the breakdown of these drugs. Hence, taking biotin might increase the side effects of certain medicines significantly if biotin increases the level of the drug in the liver. 

Here are some examples of drugs that are changed by the liver and might be affected by the intake of biotin: 

  • Haloperidol (treatment of psychotic disorders) 
  • Fluvoxamine (treatment of depression) 
  • Clozapine (an antipsychotic medication) 
  • Cyclobenzaprine (muscle relaxer) 
  • Imipramine (antidepressant) 
  • Olanzapine (treatment for schizophrenia) 

7. Kidney problems 

People who are on dialysis would have delayed clearance of biotin. Notably, biotin is a water-soluble vitamin excreted through the kidneys and the urine. When there is kidney failure, excess biotin may not be expelled sufficiently. 

8. Excessive thirst 

Overdose of biotin can lead to excessive thirst. It has been shown that biotin plays a role in controlling blood glucose levels. Excess of biotin would lead to increased breakdown of blood glucose levels in the blood, leading to hyperglycemia. When blood sugar levels are too high, this can lead to an experience of thirst [6]. 


Biotin supplement is relatively safe and tolerable even in very high doses. Since biotin is a water-soluble vitamin, any excess is excreted via the kidney and urine. However, in cases where individuals have medical conditions that prevent optimal uptake of biotin can lead to excess biotin in the bloodstream. 

When biotin is not appropriately used in the body or is present in excessively high amounts, this can lead to side effects such as insomnia or trouble sleeping, acne, digestive upset, skin rashes, interference with laboratory test results, excessive thirst and kidney problems.

Reducing high-dose biotin supplementation often resolves most of these side effects. In some cases, removing biotin supplements completely will resolve side effects. 

Considering the potential side effects when taking biotin supplementation, it is always best to consult your doctor to ensure that you are safely taking this vitamin. Taking the appropriate dose at the right time would prevent drug-to-drug interactions. 

Finally, biotin is an essential vitamin that ensures good metabolism of carbohydrates and fats. The potential side effects of this vitamin can be addressed by taking the appropriate dosage or removing biotin supplementation.

Concerns about the latter can be addressed by obtaining biotin from food. There are still no studies suggesting a potential overdose of the vitamin when this is sourced from biotin-rich foods. 

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[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2726758/ 
[2] https://www.ncbi.nlm.nih.gov/books/NBK554493/ 
[3] ​​https://pubmed.ncbi.nlm.nih.gov/33682085/ 
[4] https://pubmed.ncbi.nlm.nih.gov/29417793/ 
[5]  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6663274/  
[6] https://pubmed.ncbi.nlm.nih.gov/25997216/ 

Photograph: Lelia_Milaya/Envato
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