Bioavailability of biotin given orally to humans in pharmacologic doses

Janos Zempleni, Donald M. Mock

Research output: Contribution to journalArticlepeer-review

34 Scopus citations


Background: Patients with carboxylase deficiency are treated with pharmacologic doses of biotin. Objective: We sought to determine the bioavailability of biotin at pharmacologic doses. Design: Biotin was administered orally (2.1, 8.2, or 81.9 μmol) or intravenously (18.4 μmol) to 6 healthy adults in a crossover design with ≥2 wk between each biotin administration. Before and after each administration, timed 24-h urine samples were collected. Urinary biotin and biotin metabolites were analyzed by an HPLC avidin-binding assay. Results: Urinary recoveries of biotin plus metabolites were similar (≃50%) after the 2 largest oral doses and the 1 intravenous dose, suggesting 100% bioavailability of the 2 largest oral doses. For unexplained reasons, the apparent recovery of the smallest oral dose was about twice that of the other doses. For all 4 doses, biotin accounted for >50% of the total of biotin and biotin metabolites in urine. Bisnorbiotin (13-23%), biotin-d,l-sulfoxide (5-13%), bisnorbiotin methyl ketone (3-9%), and biotin sulfone (1-3%) accounted for the remainder. The percentage excretion of biotin was greater when biotin was administered intravenously and for the largest oral dose than for the 2 smallest oral doses. Conclusion: Our data provide evidence that oral biotin is completely absorbed even when pharmacologic doses are administered. Biotin metabolites account for a substantial portion of total urinary excretion and must be considered in bioavailability studies. We speculate that renal losses of biotin (as a percentage of the dose administered) are moderately elevated when pharmacologic doses of biotin are administered.

Original languageEnglish (US)
Pages (from-to)504-508
Number of pages5
JournalAmerican Journal of Clinical Nutrition
Issue number3
StatePublished - Mar 1999
Externally publishedYes


  • Bioavailability
  • Biotin
  • Biotin metabolites
  • Humans
  • Multiple carboxylase deficiency
  • Urine

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics

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