Biotin, also known as vitamin B7 or vitamin H, is a water-soluble vitamin that plays an essential role in metabolizing fats, carbohydrates, and amino acids. Additionally, biotin is crucial for maintaining healthy skin, hair, and nails. Most people get enough biotin naturally through their diet, but some take biotin supplements for various reasons.
The Relationship Between Biotin and Thyroid Tests
Recently, there has been growing concern that biotin supplements could interfere with thyroid function tests. The logic behind this concern is that biotin can interfere with certain tests by binding to the proteins that carry these tests in the blood. This could cause artificially low or high results, potentially leading to a misdiagnosis or unnecessary treatment.
How Biotin Affects Thyroid Tests
Biotin can interfere with different types of thyroid function tests. Below are a few examples:
- TSH (thyroid-stimulating hormone) tests: TSH tests are often used to determine whether a patient has hypothyroidism or hyperthyroidism. High doses of biotin can interfere with these tests, leading to falsely low TSH levels.
- Free T3 (triiodothyronine) tests: Free T3 tests measure the amount of T3, the active thyroid hormone, in the blood. High levels of biotin can interfere with these tests, leading to falsely high levels of T3.
- Total T4 (thyroxine) tests: Total T4 tests measure the overall amount of T4 in the blood. High doses of biotin can interfere with these tests, leading to falsely high levels of T4.
- Free T4 (thyroxine) tests: Free T4 tests measure the amount of unbound, active T4 in the blood. High levels of biotin can interfere with these tests, leading to falsely high levels of T4.
It’s important to note that not all thyroid tests are affected by biotin. For example, tests that measure antibodies (like thyroid peroxidase antibodies or thyroglobulin antibodies) are not affected by biotin.
Why Biotin Affects Thyroid Tests
Biotin can interfere with thyroid tests because it binds to biotin-binding proteins that are used to carry thyroid hormone tests in the blood. When biotin levels are high, the biotin-binding proteins can become saturated, leading to inaccurate readings on thyroid function tests.
How Much Biotin is Too Much?
It’s unclear exactly how much biotin is required to interfere with thyroid function tests. However, most studies suggest that biotin doses of 5 mg or more per day can cause interference. This is significantly higher than the recommended daily intake of biotin, which is around 30 mcg for adults.
Should You Stop Taking Biotin Before Thyroid Tests?
If you’re taking biotin supplements and are scheduled for a thyroid function test, it’s best to stop taking biotin a few days before the test. This will give the biotin levels in your system a chance to decrease, minimizing the risk of inaccurate test results.
If you’re unsure whether to stop taking biotin or not, it’s best to consult with your healthcare provider. They can provide personalized advice based on your specific situation and medical history.
Other Things that Might Affect Thyroid Tests
It’s important to note that biotin isn’t the only thing that can interfere with thyroid function tests. Other factors that might affect test results include:
- Medications, like birth control pills or steroids
- Recent surgery or illness
- Certain medical conditions, like liver disease or kidney disease
The Bottom Line
Biotin supplements can interfere with thyroid function tests, leading to potentially inaccurate results. If you’re taking biotin and are scheduled for a thyroid function test, it’s best to stop taking biotin a few days before the test. If you’re unsure whether to stop taking biotin or not, it’s best to consult with your healthcare provider. It’s also important to note that biotin isn’t the only factor that can affect thyroid function tests. Other medications, medical conditions, and recent surgeries or illnesses can also affect test results.
- Can biotin affect T3 levels?
- Can biotin cause hyperthyroidism?
- Can I take biotin and levothyroxine together?
- Can a biotin supplement cause hypothyroidism?
- How long should I stop taking biotin before a thyroid test?
Yes, high levels of biotin can interfere with free T3 tests, leading to falsely high levels of T3.
No, biotin supplements cannot cause hyperthyroidism. However, biotin can interfere with thyroid function tests, potentially leading to a misdiagnosis of hyperthyroidism.
Yes, biotin and levothyroxine (a medication used to treat hypothyroidism) can be taken together. However, it’s important to let your healthcare provider know that you’re taking both medications as they may interact with each other.
There is no evidence to suggest that biotin supplements can cause hypothyroidism. However, high doses of biotin can interfere with thyroid function tests, leading to a misdiagnosis of hypothyroidism.
It’s best to stop taking biotin a few days before a thyroid function test. However, the amount of time required to decrease biotin levels in the blood can vary based on several factors, including the dose of biotin you were taking and your body’s ability to eliminate it.