Though people do need biotin (the Daily Value for adults is 300 micrograms), this vitamin can easily be found in many foods, such as egg yolks, fish, and nuts. But biotin supplements can contain 5,000 micrograms—about 16 times higher than the Daily Value—or more. And taking biotin supplements has not been proved to have measurable benefits. “There is virtually no evidence that biotin supplements actually work to improve skin, hair, or nails,” says Marvin M. Lipman, M.D., Consumer Reports’ chief medical adviser.
What’s more, supplements in general are only loosely regulated. Though they fall under the purview of the FDA, the agency classifies them differently from drugs. The companies that make and sell them aren’t required to prove that they’re safe, that they work as advertised, or even that their packages contain what the labels say they do. “Supplement oversight is virtually nonexistent,” Lipman says. This makes it difficult to even know how much you’re actually ingesting.
Consumers may not be aware of biotin’s interference with blood tests, as supplement labels don’t carry such warnings.
“It’s great that the FDA posted a warning on its website, but most individual consumers aren’t going to see it there,” says Chuck Bell, programs director for Consumers Union, the policy and mobilization division of Consumer Reports. “Supplement manufacturers have an obligation to share this information through product labels or other means. You’ll have better healthcare outcomes if both consumers and providers are aware that medical tests could be affected by biotin use.”
“Everyone should tell their doctors about all the supplements they take, even if the doctor doesn’t ask,” advises Lipman. “If you use biotin supplements, stop taking them at least a week before having medical tests.” And if you have had a test done and are concerned about the results, the FDA suggests you talk to your healthcare provider about the possibility of biotin interference. He or she can advise you on whether more testing should be done.