If the lab results show that your thyroid function is out of whack, that could be because of the vitamin B7 (Biotin) you are taking. This is true and many health care professionals are not aware of that!
Incredible as it may seem, biotin interferes with thyroid function tests in the lab. Also known as vitamin B7 and vitamin H, Biotin is a commonly used supplement mainly for hairs and nails. It is a water-soluble vitamin and is also prescribed in medicine for diabetic neuropathy, cradle cap, and several inherited metabolic disorders such as biotin–thiamine–responsive basal ganglia disease, biotinidase deficiency and disordered metabolism of mitochondria. For more information about biotin, click on Biotin (Vitamin B7).
How Does The Interaction Occur?
Biotin interferes with the lab techniques used to detect thyroid hormones, skewing test results. In fact, it may make the lab results show falsely an underactive or overactive thyroid, depending on which measuring technique has been used.
When measuring thyroid hormones, they use either competitive methods or non-competitive methods. Competitive methods are used to measure free T4 and total T3, and non-competitive methods are used to measure TSH. When taking biotin, if a competitive method is used, the thyroid test results may falsely show an overactive thyroid, and if a non-competitive method is used, the results may show falsely an underactive thyroid.
Moreover, one of the thyroid function tests ordered by doctors is anti–thyrotropin antibody. Biotin interferes with detection of this antibody as well.
Lab Methods For Measuring Thyroid Hormones:
There is a wide range of analytical methods for measuring thyroid hormones. They include:
1) Spectrophotometric method.
2) Radioimmunoassay (RIA).
3) Enzyme-linked immunosorbent assay (ELISA).
4) Fluorescence polarization immunoassay (FPIA).
5) Chemiluminescence immunoassay (CLIA).
6) High-performance liquid chromatography (HPLC) and LC-mass-spectrometry (LC-MS).
What You Should Do?
If you are taking biotin or any biotin-containing products for some reasons and the blood test shows abnormal thyroid function, it is suggested that you discontinue taking biotin and repeat the thyroid testing few days later. Since biotin is a water-soluble vitamin, it should be out of your body within the next 72 hours after you stop taking it, which will normalize the thyroid function tests. However, to be on cautious side, we recommend you repeat the thyroid testing in 7-10 day in order to avoid unnecessary thyroid medications.
Abazar Habibinia, MD, DFN, CSDTT
Executive Director of The Canadian Academy of Sports Nutrition
