Biotin, also know as the “beauty vitamin,” has been shown to improve hair, skin, and nails.
But experts now warn this supplement may come with an ugly downside. Mounting research shows high doses of biotin can interfere with common, diagnostic lab tests, making it more difficult for doctors to read results and putting some patients at risk for mistreatment or misdiagnosis.
“Over the last 18 months, the number of cases that have reported biotin interference in the literature has increased dramatically,” says Dr. Dana Stern, one of the foremost experts on nail health.
The Food and Drug Administration has also seen an increase “in the number of reported adverse events, including one death, related to biotin interference,” leading the agency to issue a safety alert, for consumers and medical professionals.
Most documented cases are specific to thyroid testing, but experts warn many more could be impacted, for everything from hormone to cancer screenings.
“…and even things like cardiac enzymes which can measure whether a person is having a heart attack in an acute setting,” says Dr. Stern.
That’s because the assays, or tests, often used contain biotin themselves and the combination can skew certain lab results falsely positive or negative.
“So far, all of the studies have shown that interference occurs at biotin doses of 10,000 micrograms and higher,” says Dr. Stern.
That may sound like a lot, but consider this: we found several supplements marketed for hair, skin, and nails that contain 10,000 micrograms in a single daily dose. To put that in perspective, the National Institutes of Health says that most adults only need about 30 micrograms a day to “ensure nutritional adequacy.”
In addition, “A lot of patients don’t necessarily realize that they’re getting biotin from multiple supplement sources,” says Dr. Stern.
So check any bottles you have for biotin, also known as B7. In addition to supplements for hair, skin, and nails, biotin can be found in multi and prenatal vitamins. Most importantly, consult your doctor.
“The consensus is that you should stop taking biotin 48 hours to one week prior to having your laboratory results,” says Dr. Stern.
We reached out to both the Council For Responsible Nutrition and the Natural Products Association. Both groups agree that keeping your doctor in the know is key.
It’ also important to note that many foods contain biotin, including eggs, bananas, and whole wheat bread, and that normal dietary intake poses no risk of lab interference.