Does Vitamin B12 Deficiency Cause Hair Loss or Is It a Myth? Hair loss. Dermatologist said to take vitamin D and B12. Wear hair in ponytail for work and shower everyday but brush once a week. Does anyone have tips for hair loss and Vitamin B12 Injections For Hair Vitamin B12 is important for healthy hair growth because it supports cell division and oxygen supply to hair follicles. When B12 causes hair fall Hair fall can occur if there is Vitamin Scalp Vitamin Injections: Benefits, Results, and How They Work