Does biotin affect your kidneys?

October 31, 2025 •

4 min read

According to the National Institutes of Health, biotin has no established upper intake level due to its low toxicity. This often leads people to question: does biotin affect your kidneys when taken in large doses, or is it a concern for other reasons?

Quick Summary

Biotin is generally safe for healthy kidneys, as excess amounts are excreted through urine. The main risk of high-dose supplementation is interference with certain lab tests, which can lead to dangerously false results and misdiagnosis.

Key Points

No Direct Kidney Harm: Biotin does not cause damage to healthy kidneys; excess amounts are naturally excreted in urine.
Lab Test Interference: High-dose biotin is a significant concern for interfering with a variety of laboratory tests, leading to false results.
Risk of Misdiagnosis: Inaccurate lab results can cause healthcare providers to misdiagnose and mistreat patients, with potentially serious consequences, such as a missed heart attack.
Chronic Kidney Disease Caution: Individuals with pre-existing kidney conditions or on dialysis should consult a doctor before supplementing, as their clearance may be altered.
Communicate with Your Doctor: Always inform your healthcare provider about any biotin supplements you take, especially before undergoing lab work.
Stop Before Testing: To ensure accurate results, doctors may advise stopping high-dose biotin for several days before a blood test.

Biotin and Healthy Kidney Function

Biotin, also known as vitamin B7, is a water-soluble vitamin essential for various metabolic processes in the body, including the breakdown of fats, carbohydrates, and proteins. As a water-soluble vitamin, any amount not needed by the body is simply dissolved in water and excreted through urine. For individuals with healthy, properly functioning kidneys, there is no evidence that standard or even moderately high doses of biotin cause any damage. The kidneys efficiently filter the excess biotin out of the bloodstream, preventing it from building up to toxic levels. This mechanism is the reason that biotin toxicity is extremely rare in the general population. However, this does not mean supplementation is without risk, especially when considering medical care.

The Crucial Link: Biotin and Lab Tests

While biotin does not appear to directly damage healthy kidneys, its most significant impact is on medical diagnostics. High doses of biotin supplements can cause clinically significant false readings in a wide variety of laboratory tests. The issue stems from the biotin-streptavidin technology used in many common immunoassays. These tests use biotin as a key component to detect specific substances in a patient's blood. When the patient has a very high concentration of biotin from supplements, it can interfere with the test's signaling process, causing misleadingly high or low results.

Which Lab Tests Are Affected?

This interference can impact crucial tests across multiple medical fields, including:

Endocrinology: Tests for thyroid-stimulating hormone (TSH), free and total thyroxine (T4), and parathyroid hormone (PTH) can be significantly skewed. Incorrect thyroid test results can lead to misdiagnosis of conditions like Graves' disease.
Cardiology: High-dose biotin can cause falsely low troponin levels, a critical marker used to diagnose heart attacks. This can lead to a missed or delayed diagnosis with potentially fatal consequences.
Reproductive Health: Assays for hormones like follicle-stimulating hormone (FSH) and luteinizing hormone (LH) can also be affected.

Chronic Kidney Disease and Biotin

For individuals with pre-existing kidney conditions, the situation is more complex. While biotin is generally safe, those with chronic kidney disease (CKD) should always consult a healthcare provider before taking supplements. Their kidneys may have a reduced ability to clear excess biotin, although the primary concern remains the risk of test interference rather than kidney damage. Interestingly, some patients with CKD, particularly those on dialysis, may have lower biotin levels due to dietary restrictions and the dialysis process and might require a supplement. Any such supplementation must be done under strict medical supervision to ensure the dosage is appropriate and managed around lab testing schedules.

Biotin and Kidney Health: A Comparison

To summarize the key differences, here is a comparison of biotin's effects on kidney health and lab tests.


Feature	Biotin's Effect on Kidney Health	Biotin's Effect on Lab Tests
Mechanism	Excreted via urine, no known damage to healthy kidneys.	Interferes with biotin-streptavidin technology in immunoassays.
Toxicity	Very low toxicity, no established upper intake level.	No toxicity, but causes diagnostic errors, which can be harmful.
Primary Concern	Potential for altered clearance in those with kidney disease.	Falsely high or low results for critical biomarkers.
Impact	Minimal to none for healthy individuals; requires caution in CKD.	Can lead to misdiagnosis and inappropriate treatment.

Recommendations for Safe Biotin Supplementation

To minimize risks and ensure accurate medical results, follow these guidelines:

Inform your doctor: Always tell your healthcare provider about all supplements you take, especially if you are taking high-dose biotin.
Pause before tests: If you are having blood drawn for lab work, discuss with your doctor whether to stop taking biotin for several days beforehand.
Read labels carefully: Biotin is often included in multivitamins and supplements for hair, skin, and nails, sometimes in very high doses. Check the label to be aware of your intake.
Prioritize dietary sources: Most healthy individuals get sufficient biotin from a balanced diet rich in eggs, nuts, seeds, and liver, making high-dose supplementation unnecessary.

Conclusion

In summary, the question "does biotin affect your kidneys?" is typically met with reassurance for healthy individuals. Biotin is a water-soluble vitamin that your kidneys effectively excrete. However, the critical takeaway is that high-dose biotin supplementation poses a significant and often overlooked risk of interfering with a wide range of laboratory tests, from thyroid function to heart attack markers. This interference can lead to misdiagnosis and dangerous medical outcomes. By understanding this distinction and communicating openly with your healthcare providers, you can safely continue your supplementation regimen without compromising the accuracy of your medical care. For more information on this critical issue, refer to the FDA's official safety communication.

Frequently Asked Questions

No, there is no evidence to suggest that biotin supplements cause kidney stones. The primary risk of high-dose biotin is interference with certain lab test results, not the formation of kidney stones.

A true overdose on biotin is unlikely because it is a water-soluble vitamin, and the body flushes out any excess through urine. However, ingesting high doses can interfere with lab tests, which can be medically dangerous.

Many lab tests use biotin-streptavidin technology. When high levels of biotin from supplements are present in a blood sample, they disrupt this technology, causing the test to produce falsely high or falsely low readings.

A wide variety of tests are affected, including those for thyroid hormones (TSH, T3, T4), heart-attack markers (troponin), and other hormones like PTH, FSH, and LH.

You should consult your doctor, as the exact time can vary. However, many healthcare professionals recommend stopping high-dose biotin supplements for several days before a lab test to ensure accurate results.

For most healthy individuals, a balanced diet provides sufficient biotin. Deficiency is rare. Supplements are typically needed only for a diagnosed deficiency or for certain medical conditions, and should be discussed with a doctor.

Those with chronic kidney disease (CKD) should exercise caution and consult their doctor before taking biotin supplements. While not known to cause harm, their metabolism and vitamin needs may be altered, and test interference is still a concern.