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Blog: Are you taking biotin?
“Are you taking biotin?”
It seems that, lately, I have been asking this question repeatedly to my clinic patients — sometimes daily.
Last week, I saw a patient who follows with our endocrine clinic for a thyroid problem. For over 2 years, I have struggled with the interpretation of her thyroid function tests. I could not add up the lab results with her clinical status. She was asymptomatic, but her thyroid function tests have been abnormal.
“Yes, I am,” she answered.
When I asked her if she was taking biotin, she was kind of surprised, and I guess she had never been asked this question prior. At the same time, she acted as if she thought I was some kind of a genius to ask the question. I guess she may have thought to herself, wondering, “How did the doctor know that I was taking biotin?”
The rest of the dialogue went like something like this:
“How long have you been on biotin?” I asked.
“For about 4 years,” she replied.
“And what strength?” I asked.
“Five mg daily,” she replied.
“But biotin is not listed on your medications list in the EMR,” I said.
“Oh, I am sorry, I did not realize it was a medication,” she explained.
The medications are usually reviewed by our medical assistants at the check-in, and then by clinicians during the office visit. Clearly, we have missed this important piece in the patient’s medication history.
“And why have you been taking biotin?” I asked.
“For skin care,” she replied.
In our practice, we have observed lately that many patients have reported that they have been taking biotin, and likewise, the medication list did not list it.
Until we became aware of the “biotin problem,” I recall that I may have spotted biotin listed on the medication list of some patients now and then, but I had always considered biotin as a natural supplement just like many vitamins and minerals that patients buy over the counter.
So, what is the “biotin problem?”
As a hair, nail and skin beauty product, biotin (also known as vitamin B7) is marketed at doses of 5 mg and 10 mg. That translates to 5000 µg to 10,000 µg. Although it is not clearly well-established, the daily biotin requirement by the adult human body is about 30 µg to 100 µg daily, according to the Mayo Clinic’s educational website (https://www.mayoclinic.org/drugs-supplements/biotin-oral-route/description/drg-20062359).
The usual amount of biotin as an ingredient in traditional over-the-counter multivitamin formulations is about 100 µg to 300 µg. Therefore, the amount in the marketed beauty products far exceeds the daily requirement. In the case of the first patient, the 5-mg dose is at least 50 times more than the daily requirement. In the second case, it is about 200 times more.
And that is where the recently emerging biotin problem comes from.
Biotin is a component of several assays used in several laboratory tests, including thyroid and other endocrine tests.
In addition to this patient, I have encountered several patients in our endocrine clinic with similar, confusing thyroid function tests. In the perfect setting to cause confusion, such labs would typically show elevated T4 and T3, with low TSH, and with positive TSI and TRAB, or partial abnormality in the labs.
The full profile of thyroid function tests would be a perfect diagnosis of Graves’ disease.
Except that these patients did not have any symptoms or signs of Graves’ disease.
In partial lab interference, thyroid function tests can be misleading or they may not “add up,” as physicians refer to certain situations when lab tests do not add up logically to denote a disease or disorder. For example, labs may show results consistent with hypothyroidism and hyperthyroidism in the same patient.
The reason for the lab artifact has to do with the fact that many lab procedures involve immunoassay mechanisms that contain biotin. Many lab tests are affected, including those for hormones, immunoglobulins and troponin (a marker for acute heart attacks). The average, low-dose biotin contained in multivitamins is not likely to cause lab interference, but high-dose biotin products — especially the 5-mg and 10-mg tablets — can.
The exact mechanism of how biotin interferes with lab tests is sophisticated and is beyond the scope of this blog. However, the impact of this emerging problem is summarized in a brief report published in 2016 in The New England Journal of Medicine by Sebastian Kummer, MD, and colleagues (Kummer S, et al. N Engl J Med. 2016;doi:10.1056/NEJMc1602096), of Heinrich Heine University Hospital in Duesseldorf, Germany: “Thus, high-dose biotin treatment can cause insidiously misleading laboratory results by fully mimicking the typical laboratory pattern of Graves’ disease and sometimes persisting for several days after biotin application. ... This may lead to unnecessary antithyroid treatment and thereby cause unrecognized hypothyroidism that might be deleterious, especially in young children. In addition, biotin treatment potentially interferes with other streptavidin–biotin immunoassays. Although manufacturers are aware of this potential problem, this source of error is usually not referenced to the clinician in laboratory reports. Therefore, we believe that it is crucial to increase the awareness of this problem in the medical community.”
Finally, a warning was issued by the FDA in late 2017 about biotin interference in lab tests (www.fda.gov/medicaldevices/safety/alertsandnotices/ucm586505.htm). The warning stated:
“Many lab tests use biotin technology due to its ability to bond with specific proteins which can be measured to detect certain health conditions. For example, biotin is used in hormone tests and tests for markers of cardiac health like troponin. Biotin, also known as vitamin B7, is a water-soluble vitamin often found in multivitamins, prenatal vitamins and dietary supplements marketed for hair, skin and nail growth. ... Biotin in blood or other samples taken from patients who are ingesting high levels of biotin in dietary supplements can cause clinically significant incorrect lab test results.”
The FDA warned physicians about misleading lab tests in patients taking high doses of biotin, citing a fatal case of missed diagnosis of myocardial infarction: “The FDA is aware of people taking high levels of biotin that would interfere with lab tests. Many dietary supplements promoted for hair, skin and nail benefits 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. The FDA has seen an increase in the number of reported adverse events, including one death, related to biotin interference with lab tests. Biotin in patient samples can cause falsely high or falsely low results, depending on the test. Incorrect test results may lead to inappropriate patient management or misdiagnosis. For example, a falsely low result for troponin, a clinically important biomarker to aid in the diagnosis of heart attacks, may lead to a missed diagnosis and potentially serious clinical implications. The FDA has received a report that one patient taking high levels of biotin died following falsely low troponin test results when a troponin test known to have biotin interference was used.”
The FDA warning emphasized the importance of awareness by patients and physicians about biotin’s interference with labs: “Patients and physicians may be unaware of biotin interference in laboratory assays. Even physicians who are aware of this interference are likely unaware as to whether, and how much biotin, patients are taking. Since 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 (eg, when taking products generally labeled for their benefits to hair and nails).”
After a lengthy educational discussion with the patient, she appreciated this new information. She apologized again for the struggles that I had endured in trying to figure out her abnormal thyroid function tests. We mutually agreed that she stop biotin for several days (a minimum of 3 days is recommended) and to repeat thyroid function tests off biotin. In several other patients whom we encountered over the last several months since we have become aware of the biotin problem, thyroid function tests normalized after stopping biotin.
My last question to the patient was:
“For what reason did you take biotin?”
“For skin care for forearms and hands,” she replied.
“Did it help?” I asked.
“Absolutely,” she said. She stated that since using biotin, her skin became soft and healthy. Healing from trauma would be quick and with no scars left as compared to pre-biotin time. And when I asked other patients about beauty effects on hair and nails, many patients confirmed benefits.
I explained to the patients and all other prior patients that I am not saying biotin is toxic, and indeed it may be beneficial for hair-skin-nail health. All I am advocating is that biotin may interfere with labs, so it should be stopped for several days before any lab test.
And, as important, I advised all these patients to make sure they mention biotin at any doctor visit, or hospital encounter, so biotin will be included on the medication list.