Who doesn’t want better skin and longer, stronger hair and nails? Taking a biotin supplement has become a no-brainer for millions of women, but the FDA is warning that the vitamin can “significantly interfere with certain lab tests” and cause incorrect test results, according to a release .

“The FDA has seen an increase in the number of reported adverse events, including one death, related to biotin interference with lab tests,” the release reads. Also known as vitamin B7, biotin can cause falsely high or incorrectly low results, depending on the test, when found in high levels in patient samples.

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“The FDA is aware of people taking high levels of biotin that would interfere with lab tests,” the release states, explaining that many dietary supplements promoted for hair, skin, and nail benefit s can contain biotin levels up to 650 times the recommended daily intake of biotin. “Physicians may also be recommending high levels of biotin for patients with certain conditions such as multiple sclerosis (MS). Biotin levels higher than the recommended daily allowance may cause interference with lab tests.”

But, it’s not just consumers that are unaware of the reason for these skewed results. The FDA explains that patients and physicians may be unaware of biotin interference in lab tests, adding that even physicians who are aware of this interference are probably unaware as to whether, and how much biotin, their patients are taking. “Because patients are unaware of biotin interference, patients may not report taking biotin supplements to their physicians, and may even be unaware they are taking biotin.”

To err on the side of caution, if you take a biotin supplement, or incorporate anything into your diet that contains the vitamin (be sure to read your labels), tell your doctor. “Be aware that some supplements, particularly those labeled for hair, skin, and nail benefits, may have high levels of biotin, which may not be clear from the name of the supplement,” reads the release.

“If you have had a lab test done and are concerned about the results, talk to your health care provider about the possibility of biotin interference.”