Biotin (Vitamin B7)

What is biotin?

Biotin is an essential vitamin that has been grouped with the B-complex vitamins since it was discovered in yeast alongside other B vitamins. Although it is technically known as vitamin B7, this designation is not too common as it is usually simply referred to as biotin. It was initially found to be a component of nails, skin, and hair to a relatively high degree.

What are biotin’s main benefits?

Biotin has been seen as the go-to vitamin for beauty ever since one pilot study in women with brittle nails showed supplementation to be beneficial. It is currently being marketed for improving nail, skin, and hair aesthetics. These claims, however, were not followed up scientifically so there is not much evidence to support biotin's role here. It can plausibly have these actions mechanistically, but there is simply not much evidence that can be used as support. Overall, aside from instances where biotin may be deficient (alcoholism, some epileptic drug therapies, and overconsumption of raw egg whites) the supplement does not have any solid evidence for benefits and may have a role as a beauty supplement pending better evidence.

What are biotin’s main drawbacks?

Currently, while there is no evidence to suggest that biotin intake at levels well above the adequate intake levels of 5–35 mcg/day is toxic in humans, there are other risks to consider. For one, excessive biotin intake can imitate some of the signs and symptoms of diabetes, such as excessive thirst and urination. Further, biotin supplementation can cause inaccurate results on multiple categories of medical lab tests. Case studies and comparative tests have shown that biotin may cause inaccurate lab results in immunoassays that use biotin-streptavidin technology. Abnormally high or low readings as a result of biotin supplementation of as little as 10 mg/day could lead to misdiagnosis of pregnancy, thyrotoxicosis, Graves’ Disease, and even heart attack. Biotin concentrations are detectable in blood samples, which may help clinicians to assess whether biotin has affected a particular test result. Detectable levels of biotin have also resulted in false labs for serum tests including CK-MB, human chorionic gonadotropin (HCG, a hormone produced in pregnancy and some cancers), troponin, cortisol, ferritin, TSH, T3, T4, PTH, 25OHD, and prolactin; biotin may affect children’s and adults’ tests differently, and its effects on serum labs can also depend on intake levels.

How does biotin work?

Biotin's general role as an enzymatic cofactor has also led to some research suggesting it may interact with glucose metabolism in the human body. As a general statement, it seems that in rodents with a higher circulating biotin level in their blood, the amount of insulin released in response to a glucose test is higher, leading to less elevation of glucose over time. This rodent evidence also reports that the higher glucose is not met with higher insulin resistance, suggesting a potentially beneficial role. Not too much evidence has been conducted in humans in regard to diabetes, with one study finding that intramuscular biotin was able to attenuate symptoms of neuropathy in three diabetic subjects.