Food, Herbs & Supplements

Biotin, also known as vitamin B7, is a water-soluble vitamin that is widely recognized for its purported benefits in promoting healthy hair, skin, and nails. However, the evidence supporting its efficacy for these purposes remains inconclusive. While a deficiency in biotin can lead to hair loss, skin issues, and brittle nails, most individuals obtain sufficient biotin through their diet, which includes foods like beef liver, eggs, salmon, avocados, sweet potatoes, and seeds. Certain groups, such as individuals with alcohol dependence and women who are pregnant or breastfeeding, may require additional biotin supplementation.

Biotin plays a crucial role in several metabolic processes. It helps enzymes in breaking down fats, carbohydrates, and proteins, and it regulates cell signaling and gene activity. This essential nutrient is naturally present in many foods and is available as a dietary supplement. Despite its popularity, there is no Recommended Daily Allowance (RDA) for biotin due to insufficient evidence supporting a specific daily requirement for healthy individuals. The average recommended amount for adults is 30 micrograms per day.

Biotin’s role in enzyme function is critical. It acts as a cofactor for five carboxylases: propionyl-CoA carboxylase, pyruvate carboxylase, methylcrotonyl-CoA carboxylase, acetyl-CoA carboxylase 1, and acetyl-CoA carboxylase 2. These enzymes are involved in the metabolism of fatty acids, glucose, and amino acids, highlighting biotin’s importance in maintaining metabolic health. The nutrient also contributes to the formation of fatty acids, which nourish the skin, suggesting a possible mechanism for its perceived benefits in skin health.

Despite its essential role in the body, there is a lack of robust scientific evidence to support the widespread use of biotin supplements for improving hair, skin, and nails. Several small studies and case reports have suggested benefits, but these studies often have significant design flaws, such as the lack of a placebo group and unclear baseline biotin status of participants. Reports of hair growth benefits are primarily anecdotal and often involve children, further emphasizing the need for more rigorous research.

One of the concerns with high biotin intake is its potential to interfere with diagnostic tests. Excessive biotin can affect assays that use biotin-streptavidin technology, commonly employed to measure hormone levels, including thyroid hormones. This interference can result in falsely normal or abnormal results, leading to misdiagnoses of conditions like Graves' disease and severe hyperthyroidism. The FDA has issued warnings about this issue, noting that biotin levels nearly 600 times the RDA can cause such interference. Recent case reports have described instances of false indications of Graves' disease and severe hyperthyroidism in patients taking 10-300 mg of biotin per day.

Biotin can also interact with certain medications. For example, anticonvulsant treatments for epilepsy have been associated with lower serum biotin levels, likely due to increased biotin catabolism and reduced intestinal absorption. Medications such as carbamazepine, primidone, and phenobarbital can increase the metabolism of biotin, leading to a deficiency in some individuals.

In conclusion, while biotin is an essential nutrient for various metabolic processes and overall health, its use for enhancing hair, skin, and nails is not strongly supported by scientific evidence. The nutrient’s role in metabolic conversions, including fatty acid formation, contributes to its perceived benefits for skin health. However, caution is advised when using biotin supplements, considering their potential to affect diagnostic tests and interact with certain medications. Future research is needed to provide more definitive answers regarding biotin’s efficacy and safety, particularly in high doses. Until then, individuals should aim to meet their biotin needs through a balanced diet, reserving supplements for those with a demonstrated deficiency or specific medical conditions that warrant additional biotin intake.

Zempleni, J., Wijeratne, S.S.K. and Hassan, Y.I. (2009), Biotin. BioFactors, 35: 36-46. https://doi.org/10.1002/biof.8

Patel, D. P., Swink, S. M., & Castelo-Soccio, L. (2017). A Review of the Use of Biotin for Hair Loss. Skin appendage disorders, 3(3), 166–169. https://doi.org/10.1159/000462981