Pat asked
I just received my annual lab results. My T4 is normal but my TSH is quite high. I have been taking Biotin 2500 mg daily for about 6 months. I read that Biotin can affect the results of TSH levels. My MD is away for 2 weeks. Questions: 1) Could my results be incorrect as a result of the biotin? How long should I wait before I could get an accurate result after discontinuing the biotin? 2) I would prefer not to take a synthetic hormone treatment if my results are still elevated. Can you suggest an alternative?
At a glance
- Biotin can affect TSH lab test results, generally causing falsely low TSH levels.
- Most studies suggest not taking biotin supplements within 8 hours of a TSH test, but a longer discontinuation period may be necessary if you take biotin daily.
Answer
Yes, recent studies have shown that biotin can affect the results of TSH (Thyroid Stimulating Hormone) tests.
It is recommended to avoid biotin supplementation for at least 8 hours to avoid this interference.
What Is Biotin?
Biotin, also known as vitamin B7, vitamin H and co-enzyme R, is an essential water soluble vitamin, important for a variety of physiological processes in humans.
Although dietary intake of biotin is generally sufficient for most individuals, it is a popular over the counter supplement, commonly used for:
- Prenatal nutrition
- Hair loss
- Brittle nails
- Neuropathy
- Muscle cramps
- Multiple sclerosis
Biotin Lab Test Interference
It has been well documented that biotin supplementation can interfere with several laboratory tests, not just tests involving the thyroid. Most studies note that small doses of biotin (~30 mcg) aren't likely to significantly affect lab values, but it is certainly a possibility with high doses (>30 mcg).
There are several theories as to why biotin can affect lab tests (i.e. TSH tests):
- Biotin may block test assay signals, leading to falsely elevated test results.
- Biotin may compete with biotin-containing complexes the test utilizes, which can lead to falsely low results.
Exactly which lab tests are potentially affected by biotin, and by what extent, isn't well known and evidence suggests that there may even be variability from test to test or with tests from different manufacturers.
In November 2017, the FDA released a safety communication warning about biotin supplementation and lab tests:
References
- Biotin interference on TSH and free thyroid hormone measurement. PubMed
- Interference by biotin therapy on measurement of TSH and FT4 by enzyme immunoassay on Boehringer Mannheim ES700 analyser. PubMed
- The FDA Warns that Biotin May Interfere with Lab Tests: FDA Safety Communication. FDA
- Biotin Interference in Diagnostic Tests. PubMed
- More on Biotin Treatment Mimicking Graves' Disease. PubMed
- High doses of biotin in chronic progressive multiple sclerosis: a pilot study. PubMed
- Biotin ameliorates muscle cramps of hemodialysis patients: a prospective trial. PubMed
- Biotin for diabetic peripheral neuropathy. PubMed
- Biotin in metabolism and its relationship to human disease. PubMed
- Biotin in human nutrition. PubMed
