Red onion shampoo, When added to the hair and scalp, onion juice can provide extra sulfur to support strong and thick hair, thus preventing hair loss and promoting hair growth. The sulfur from onions may also help promote collagen production. Collagen, in turn, helps the production of healthy skin cells and hair growth. Red onion is important because it helps in blood circulation. It also contains Extracts of Amla. Amla oil helps boost blood circulation. This provides nourishment to the follicles and increases the growth of the hair. It strengthens the scalp and hair. It prevents or treats dandruff and dry scalp. Amla oil helps boost blood circulation.