Onion has sulfur which helps to grow healthy skin cells and ultimately helps in hair growth. Applying onion juice to scalp could increase your blood circulation which improves your hair growth and health. Grate the onion into extract water and get the onion juice, half of the onion is enough for one time use then add 1TBsp of Olive Oil, mix it and start massaging it on your scalp. Leave it for at least 30 minutes or more if you can then wash. It also leaves your hair smooth and shiny.