The onion juice is excellent to stimulate blood circulation and expedite hair growth. Onion helps prevent premature graying of hair. You can either eat it orally or apply onion extract on the scalp
Onion is rich in sulfur. This mineral is one of the main building blocks of hair. It improves blood circulation and provides the hair follicles with sufficient nourishment. Onion also has anti-bacterial properties, so it helps with scalp infections that might contribute to hair loss. Furthermore, it contains the enzyme catalase, which is an anti-oxidant that can prevent premature graying.
Onion’s potential as a potent home remedy for hair loss has also been studied scientifically. In 2002, the Journal of Dermatology published a small study that looked into the use of onion juice for alopecia areata (an autoimmune disease that presents with patchy hair loss). 84% of participants who applied onion juice twice daily for two months experienced much better hair re-growth rates compared to those who only used tap water. Men had better success with the treatment than did women.