Vitamin B7 (Biotin)

Biotin is a B-vitamin found in many foods. Biotin helps turn the carbohydrates, fats, and proteins in the food you eat into the energy you need. Signs of biotin deficiency include skin rashes, hair loss, and brittle nails. For this reason, biotin supplements are often recommended for hair, skin, and nail health.

(https://ods.od.nih.gov/factsheets/Biotin-HealthProfessional/)