Biotin Supplements

Biotin helps enzymes involved in using fats, carbohydrates and amino acids. Deficiency can affect hair and skin, but it is uncommon in people eating a mixed diet. Evidence that treating deficiency helps does not establish that high doses improve hair in someone whose biotin status is adequate.^{See reference 1}

The U.S. adequate intake for adults is 30 micrograms (mcg) per day, counting food and supplements. This is a nutritional reference amount, not a recommended cosmetic supplement dose. A supplement marketed for hair may contain a much larger quantity.^{See reference 1}

There are 1,000 micrograms in one milligram. A 5 mg tablet therefore contains 5,000 mcg. The larger-looking number may simply be a different unit. Check the amount per tablet and per labelled serving, and check multivitamins or combination products for additional biotin. These examples explain units; they do not recommend taking these amounts.

Some laboratory methods use biotin-related chemistry. Supplement biotin can disrupt that process, giving falsely high or falsely low results depending on the assay. The FDA highlights falsely low troponin results, which can interfere with assessment of possible heart injury. Not every test or laboratory method is affected.^{See reference 2,See reference 3}

In a small 2017 study, six healthy adults took 10 mg daily for seven days. Some of the tested laboratory assays showed interference and others did not. This is direct evidence of a measurement problem; it does not estimate how often a person taking a supplement will receive a misleading result.^{See reference 4}

Tell the clinician and laboratory the product name, biotin amount, usual schedule and time of the last dose. The appropriate plan depends on the assay, dose and clearance from the body, including kidney function. The laboratory may use another method or advise when to collect a sample.^{See reference 3}

There is no single pause interval that works for every dose and test. Follow advice from the ordering clinician and laboratory, and do not stop prescribed treatment yourself. If a result conflicts with symptoms or other tests, mention biotin again so interference can be considered.^{See reference 3}