Sulphur is the building block of hair. Onions being rich source of sulphur help in providing the required nourishment and helps in hair growth. It also offers cleaning properties.Onion juice helps improve hair growth by boosting the level of an antioxidant enzyme catalase. It helps nourish your hair follicles with its rich content of sulfur. Onion’s rich antibacterial properties along with other oils help keep your scalp healthy and free of infection, promoting hair growth.