Cantharidine Oil can provide extra sulfur To support strong & thick hair thus preventing hair loss and promoting hair growth. Sulfur from this oil also helps to Promote collagen 'production. Collagen in turn helps the production of healthy skin cells & hair growth. Khadi Herbal Red Onion Hair Growth Oil 100% Natural & Pure â Promote Hair Growth Prevent Hair Fall. Scalp infections & dandruff. Onion Oil is rich in Sulfur. which is known to breakage and thinning. Onions have potent anti-bacterial properties and help fight infection of the scalp. This in tan helps reduce hair fall as scalp infection can cause massive loss of hair.