Vitamin B7 (Biotin)
Biotin, also known as Vitamin B7, is critical in metabolising fats, proteins, and carbohydrates. It's found in eggs, almonds, and spinach and is essential for maintaining healthy hair, skin, and nails. Biotin deficiency can lead to hair loss and skin rashes. While the exact daily requirement is not established, it is believed to be around 30 mcg for adults. Excess biotin intake is usually not harmful as it is water-soluble.