Known as the vitamin supplement that is good for nail, and hair growth & strengthening, Biotin is commonly called Vitamin B7. It can be incorporated into the water phase of a formulation, or placed into capsules to make your own B7 supplement.
As a dietary supplement, a 100mg daily (rounded 1/64th tsp), or as directed by physician.
For topical: no set requirements have been created, but suggested levels appear to be around 0.5%.
This biotin is a standardized supplement, meaning it contains 1% biotin and 99% dicalcium phosphate which acts as the carrier. Biotin is water soluble, but the dicalcium phosphate is barely water soluble. If your formulation contains any acidic ingredients, it is recommended to break the biotin down into the acidic ingredients first.