Biotin Intake Calculator

Adequate Intake for biotin is 30 mcg daily for adults 19+ (Food and Nutrition Board, no RDA due to limited dose-response data — AI based on observed intakes of healthy populations). This calculator checks your estimated intake as percent of AI, showing whether habitual diet covers needs without supplements — most Western diets deliver 35–70 mcg, so adequacy is the norm, not the exception.

Rich food sources split into high-bioavailability animal foods (egg yolk ~10 mcg per large cooked egg, liver ~30 mcg per 3 oz, salmon) and plant foods where biotin is often bound (whole grains, nuts, legumes). Raw egg white contains avidin, which binds biotin tightly and blocks absorption — the reason raw-egg regimens can induce deficiency despite high intake on paper. Cooking denatures avidin and restores availability.

Bioavailability and gut synthesis complicate the math: colonic bacteria produce biotin, but quantitative contribution to status remains debated, and food-matrix binding means label values overstate absorbed amounts for some plant foods. Unlike most vitamins, biotin circulates at very low concentrations and is efficiently recycled, so status reflects turnover more than recent meals.

Deficiency is genuinely rare outside prolonged parenteral nutrition without biotin, chronic raw-egg-white consumption, severe alcoholism, and certain inborn errors (biotinidase deficiency, holocarboxylase deficiency). When it occurs, findings progress from hair thinning and brittle nails to periorificial rash, conjunctivitis, ataxia and depression — nonspecific enough that testing beats symptom-guessing.

Excess is low risk: no Tolerable Upper Intake Level has been set because high-dose biotin (5–10 mg, 150–300× AI) from supplements is rapidly excreted water-solubly with little acute toxicity. The real hazard is assay interference — megadose biotin falsely depresses troponin and falsely elevates or suppresses thyroid, hormone and tumor-marker immunoassays, causing misdiagnosis. Labs now flag biotin interference; stop high-dose biotin 48–72 hours before testing unless directed otherwise.

Hair, skin and nail marketing vastly outruns evidence: trials show benefit only in true deficiency or brittle-nail syndrome, not in replete individuals. A 30 mcg AI maintained by varied diet plus a single egg already exceeds needs; 5 mg beauty doses lack proven upside in non-deficient adults, while creating lab-interference downside. This tool screens adequacy, not cosmetic dosing.

For tracking, log a 3-day average rather than a single day: biotin content varies by brand and cooking method, and daily intake swings 10–20 mcg even on consistent diets. Averaging smooths noise and reveals true adequacy versus one good or bad day.

For practical tracking, log a 3-day average including one weekend day: biotin content varies by brand, batch and cooking method, and daily intake swings 10–20 mcg even on consistent diets. Averaging smooths noise and reveals habitual adequacy versus one good or bad day. If you take a multivitamin, add its labeled biotin to food estimates — many multis already contain 30–100 mcg, often pushing totals to 200%+ of AI without megadoses. High-dose beauty products (5–10 mg) should be logged separately from dietary adequacy, since they drive lab interference without improving replete status.