Use of over-the-counter biotin (vitamin B7) supplements, often marketed as a way to improve the quality of skin, nails, and hair, nearly led to an unnecessary invasive surgical procedure when the product clouded a patient’s test results.
A case report published online ahead of print in Journal of the Endocrine Society (May 10, 2018) describes a patient who was taking a 5000 µg dose of biotin daily. The recommended daily intake of biotin for adults is 30 µg per day, but supplements containing much higher doses are commonly sold over-the-counter, without a prescription, according to a press release from the University of North Carolina in Chapel Hill, N.C., where the paper’s authors are based.
The supplements are marketed as being good for healthy hair, skin and nails, though there is a lack of scientific evidence to support this claim.
After the patient, a perimenopausal woman, presented with palpitations, hirsutism, and inability to lose weight, laboratory tests led to a suspicion of hypercortisolemia or a testosterone-producing tumour. This led to weeks of psychological distress and an invasive surgery being scheduled before the abnormal lab results were tracked back to the biotin supplementation, the authors note in the case report.
“The literature is lacking with regard to biotin interference with serum cortisol and testosterone immunoassays, as in our case-report,” said senior author Dr. Maya Styner, in the release. Dr. Styner is an associate professor of endocrinology and metabolism in the department of medicine at the University of North Carolina. “Patients are ingesting supplements in a higher frequency, and higher doses, and therefore this case is timely and relevant from both a clinical and basic-science perspective.”