Biotin (Vitamin B7) and Fertility Tests

Biotin (Vitamin B7) and Fertility Tests

Biotin (also known as vitamin B7, vitamin H, or coenzyme R) when taken in high levels can affect fertility test results.  

What is biotin?

Biotin is a B vitamin (B7) that your body needs to help convert food into usable energy. It also helps regulate your genes and how cells communicate with each other. It’s found naturally in offal, eggs, yeast, milk, and sweet potatoes and at lower levels in many other foods.  

Most people get enough biotin in their diet, so deficiency is quite rare, however, as the major symptoms of biotin deficiency include brittle nails and hair, this has led many people to believe that biotin supplements will improve hair and nails in everyone. Supplement manufacturers have capitalised on this by including high doses of biotin in “hair, skin, and nails” formulations. However, there’s little evidence that biotin can help improve hair, skin, or nail health in people who don’t have a biotin deficiency.

Risks and side effects of biotin

Most multivitamins contain about 30 micrograms of B7.  High-dose hair and nail supplements on the other hand often contain up to 10mg.  Biotin isn't toxic and most people don’t seem to have any problems taking biotin supplements and any excess is excreted in the urine. There is a hidden risk though - biotin has been proven to interfere with lab tests giving erroneous results.

High-dose biotin can produce a dangerous combination of positive and negative interference among the thyroid tests (free thyroxine, free triiodothyronine, thyroid-stimulating hormone, and thyroid-stimulating hormone receptor antibodies).  Interference with parathyroid hormone, follicle-stimulating hormone, luteinizing hormone, sex-hormone binding globulin, estradiol, progesterone, testosterone, cortisol, folate, vitamin B12, and ferritin testing has also been reported.  These of course are routinely tested if you are going through infertility.

Further, biotin at doses greater than 5 mg per day can cause falsely low AMH test results.


B7 hair, skin, and nail supplements are safe to take, but if you plan of having an AMH or other fertility tests it's best to stop taking them for a couple of days prior to your tests.  B7 levels in pre-conception supplements such as Elevit, however, are perfectly safe and can be continued.