Biotin is a water-soluble B vitamin (vitamin B7) that human cannot synthesise and therefore depend on dietary and supplements intake.
It was established as a vitamin after 40 years of additional research after its initial discovery in 1927. 
Dietary biotin exists in protein-bound and free forms. However, most of the biotin in foods is bound to protein and very little dietary biotin is in the free form. [1,2]
- Dietary biotin bioavailability ranges from 5% to 100% and differs from one food source to another. 
- Free biotin is absorbed almost 100%, whereas the protein-bound biotin is converted to free biotin prior to absorption in the small intestine. [5,6]
- Being a water-soluble vitamin, it is not stored in the body and hence daily intake is recommended.
- Almost 50% of ingested biotin is excreted unchanged in urine. 
Recommended Daily Intake
Biotin Food Sources
Excessive Intake/ Toxicity Side Effects
Toxicity is rare due to the limited intestinal absorption of biotin. [1,3]
Groups At Risk of Biotin Deficiency
Biotin Interaction With Other Nutrients
- Pantothenic acid – Large doses of pantothenic acid have the potential to compete with biotin for intestinal and cellular uptake.