Can Biotin Cause Dizziness? Unpacking the Side Effects

October 20, 2025 •

3 min read

While biotin is generally considered a safe water-soluble vitamin, some individuals experience side effects, and some sources note that biotin may cause dizziness occasionally. This leads to the question of whether this popular supplement is truly the cause or if other factors are at play.

Quick Summary

Biotin rarely causes dizziness, but it can be a sign of a severe allergic reaction or potentially related to very high doses. Normal supplemental intake is considered safe and well-tolerated by most people.

Key Points

Dizziness is Not a Common Side Effect: For the vast majority of people, biotin supplementation does not cause dizziness, as it is a water-soluble vitamin with a low risk of toxicity.
Link to Rare Allergic Reactions: Severe dizziness can be a symptom of a very rare, serious allergic reaction to biotin, known as anaphylaxis, which requires immediate medical attention.
High Doses and B6: Some theories suggest very high doses of biotin might affect neurological function and vitamin B6 levels, potentially leading to dizziness, though this is not clinically well-supported.
Lab Test Interference is a Real Risk: A more significant and documented risk of high-dose biotin is its ability to interfere with laboratory test results, which can lead to misdiagnosis.
Consult a Professional: If you experience persistent or severe dizziness while taking biotin, stop taking the supplement and consult a healthcare provider immediately to determine the cause.
Consider Other Causes: Dizziness is a common symptom with many potential causes, including medications and underlying conditions, so it should not be automatically attributed to biotin.
Focus on Dietary Intake: For most healthy individuals, getting biotin from a balanced diet is sufficient, and supplementation may not be necessary.

Is Dizziness a Common Side Effect of Biotin?

For most people, dizziness is not a common side effect associated with biotin supplementation. Biotin, or vitamin B7, is a water-soluble vitamin, meaning the body does not store excess amounts. Instead, any surplus biotin is typically excreted through urine, making it difficult to reach toxic levels. Numerous studies and health institutions, including the Mayo Clinic, indicate that biotin in doses up to 10 mg per day generally does not cause side effects. The link between biotin and dizziness is usually limited to specific, rare circumstances.

Rare Allergic Reactions

One of the most documented causes linking biotin and dizziness is a severe allergic reaction, known as anaphylaxis. While exceedingly rare, this can occur with any supplement or medication. In this instance, dizziness is part of a cluster of serious symptoms that require immediate medical attention. Other signs of a severe allergic reaction can include:

Swelling of the face, tongue, or throat
Difficulty breathing or wheezing
Hives or skin rash
Rapid heart rate

Extremely High Doses and Other Factors

Some anecdotal reports and less authoritative sources suggest that extremely high intake of biotin might play a role in neurological symptoms, potentially affecting the body's vitamin B6 levels and leading to dizziness. However, this is not a widely reported or well-substantiated clinical finding in standard medical literature. The doses required to potentially cause such effects would be far beyond the typical dosage found in supplements for hair, skin, and nail health. Other conditions, such as interactions with medication, can also cause symptoms like dizziness that might be mistakenly attributed to biotin.

Differentiating Biotin Side Effects from Other Causes

It is important to determine whether the dizziness is truly a result of biotin or an unrelated issue. A physician or pharmacist can help assess the situation. The following comparison table highlights key differences between typical biotin side effects and more serious or unrelated symptoms.


Feature	Common Biotin Side Effects (Rare)	Severe Allergic Reaction (Very Rare)	Unrelated Causes of Dizziness
Symptom Profile	Mild digestive upset (nausea, stomach cramps), excessive thirst, urination	Sudden and severe dizziness accompanied by hives, swelling, and trouble breathing	Lightheadedness, vertigo, ear issues, low blood pressure, dehydration, medications
Onset	Gradual, if at all	Immediate or soon after taking supplement	Can be sudden or gradual, depending on the cause
Severity	Typically mild and temporary	Requires immediate medical attention	Varies depending on the underlying cause
Action Required	Consult a doctor if concerned, often resolves by stopping supplement	Seek emergency medical help immediately	Consult a doctor for proper diagnosis

Biotin, Lab Tests, and Misdiagnosis

While direct toxicity is rare, one of the most significant risks associated with high-dose biotin supplementation is its interference with laboratory tests. The FDA has issued warnings about this interaction, noting that it can cause falsely high or low results for tests measuring troponin (a heart attack marker), thyroid hormones, and others. A misdiagnosis resulting from inaccurate test results could lead to inappropriate medical management and could be the true underlying cause of a patient's symptoms, including dizziness, rather than the biotin itself. For this reason, it is crucial to inform your doctor about any supplements you are taking before any blood tests are performed. For more details on this phenomenon, the NIH's Office of Dietary Supplements provides a comprehensive overview.

Conclusion: Can Biotin Cause Dizziness?

Dizziness is not a typical side effect of biotin. The most direct link is its occurrence as part of a very rare, severe allergic reaction. Outside of this, reports of dizziness caused by biotin are often anecdotal or related to extraordinarily high doses that are not clinically recommended. For the vast majority of people taking biotin supplements, the risk of experiencing dizziness is low. However, high-dose biotin does pose a well-documented risk of interfering with lab test results, which can lead to misdiagnosis of other health issues. If you experience dizziness or any other unusual symptoms after starting a biotin supplement, you should discontinue use and consult a healthcare provider to rule out an allergic reaction, medication interaction, or an unrelated medical condition. Never ignore persistent or severe dizziness.

How to Minimize Risks

Always inform your doctor about all supplements you take.
Disclose biotin use before any lab work.
Stop taking the supplement and seek advice if you experience unusual symptoms like dizziness.
Adhere to recommended dosages unless advised otherwise by a medical professional.
Recognize that for most healthy individuals, dietary intake is sufficient, and supplements may not be necessary.

Frequently Asked Questions

Biotin rarely causes dizziness. When it does occur, it is most often associated with a very rare, severe allergic reaction. In most cases, dizziness experienced while taking biotin is due to other, unrelated factors.

If you experience dizziness after taking biotin, it is important to consider the severity and other accompanying symptoms. If it is part of a severe allergic reaction (along with swelling, hives, or breathing issues), seek immediate medical help. Otherwise, consult a doctor to explore other potential causes like medication interactions or unrelated conditions.

Biotin toxicity is extremely rare because it is a water-soluble vitamin and excess amounts are flushed from the body. While some anecdotal reports link high doses to dizziness, it is not a clinically established side effect of biotin toxicity.

High doses of biotin can interfere with many laboratory tests, leading to false results for things like thyroid hormones or heart attack markers. A misdiagnosis based on these false results could potentially be the real cause of symptoms like dizziness, rather than the biotin itself. Always inform your doctor if you take biotin before any lab tests.

Common side effects from biotin are rare but may include mild digestive issues like nausea or stomach cramps, or potentially increased thirst and urination at very high doses. For most people, even with supplementation, there are no side effects.

You should stop taking biotin and see a doctor if you experience persistent or severe dizziness, or any symptoms suggestive of a serious allergic reaction, such as swelling or difficulty breathing. It's always wise to consult a healthcare provider when experiencing unusual symptoms after starting a new supplement.

While biotin itself has minimal drug interactions, some seizure medications can affect biotin levels, and some theories suggest high biotin might impact other vitamins. If you take other medications, especially anticonvulsants, discuss supplement use with a doctor, as an interaction could be the cause of dizziness.