Vitamin B7
Biotin helps metabolize fats, carbohydrates and protein.
The formula matches the form shown in the 3D model. Other forms of this vitamin can have different formulas.Loading molecular structure…
D-biotin · Drag to rotate
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One representative form. Hydrogens omitted; bonds simplified.
PubChem · CID 171548Where you can find it
- Eggs
- Fish
- Nuts & seeds
- Sweet potatoes
- Spinach
What it does in the body
Biotin helps enzymes process nutrients into energy.
Recommended amounts & upper limit
US reference values for healthy adults aged 19–50, excluding pregnancy and breastfeeding. These are daily dietary intakes, not blood-test ranges or prescribed supplement doses. Other ages and life stages have different needs; see the original source.
- Men · AI
- 30 mcg/day
- Women · AI
- 30 mcg/day
- Upper limit · UL
- No established ULNo established toxicity-based UL; laboratory interference remains a risk.
How to read these levels
RDA means Recommended Dietary Allowance; AI means Adequate Intake, used when an RDA cannot be set. The upper limit (UL) is not a target or an exact toxicity threshold. Going below the RDA on one day does not diagnose deficiency. No established UL does not mean unlimited amounts are safe.
mg = milligrams; mcg = micrograms. 1 mg = 1,000 mcg. IU is vitamin-specific and cannot be converted with one rule for all vitamins.
What happens when the balance changes?
These are possible effects, not a diagnosis or a prediction from one low or high result.
Too little
Rare deficiency can cause hair thinning, skin rash, brittle nails and neurological symptoms.
Body areas affected
Hair, skin, nails and nervous system.
Too much
High supplemental biotin can produce misleading laboratory results, including some hormone tests. This may lead to incorrect clinical decisions.
Body areas affected
Laboratory assessment; direct organ toxicity is not established.
What about blood-test levels?
Blood-test levels and daily intake use different units and cannot be compared directly. Test methods, reference ranges and clinical context vary. Symptoms alone cannot establish a vitamin deficiency or toxicity; a clinician can decide which tests and treatment are appropriate.
The body connection
Rare deficiency can affect skin, hair and the nervous system.
Explore whole bodyIn Whole Body, use the Systems panel to explore the relevant body systems.