A hair pill can hold 650 times the biotin you are meant to get
The US Food and Drug Administration says many hair, skin and nail supplements hold 20mg of biotin, and some pills 100mg. The recommended daily intake is 0.03mg.
What the study found
A hair supplement commonly holds 20mg against a recommended 0.03mg
The US Food and Drug Administration says it knows of many hair, skin and nail supplements containing 20mg of biotin, and some pills containing 100mg with instructions to take more than one. The recommended daily intake is 0.03mg. That is up to 650 times, by the agency's own reckoning.
The caveat · Doses the agency knew of in 2019
The dose figures are what the agency was aware of in 2019, not a survey of what is on shelves now. The 0.03mg intake figure is itself extrapolated from the biotin content of human milk rather than measured against a requirement, and no Recommended Dietary Allowance was ever set, for lack of evidence.