What deficiencies cause hairloss?
Vitamins such as Vitamin A, E, D, B12, Roboflavin, biotin and folate are important for hair growth. Micronutrients such as zinc, selenium and iron, if deficient can cause hair loss and /or greying
Hair always grow according to its growth cycle but the total transition to old normal hair depends on the cause of hair loss. If hair loss is secondary to genetics then re-growth is doubtful unless a medical intervention is done. Hair loss secondary to infection, nutritional deficiency and damage may regrow once the cause is taken care.