· Zinc contributes to the maintenance of normal hair and nails and helps protect cells against oxidative damage.· Biotin contributes to the maintenance of normal hair and skin and participates in the normal metabolism of macronutrients.· Vitamins B1, B2, B5, B6 and B12 contribute to normal energy metabolism and help to reduce tiredness and fatigue.· Vitamin B2 contributes to the protection of cells against oxidative damage and to the maintenance of normal skin.· Sulphur amino acids, such as methionine and cystine, form part of the body’s protein structure and are naturally present in tissues such as hair and nails, within a balanced diet.