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 Hair Loss Issue, Are your hair falling out? One major reason for hair fall could be a deficiency of Vitamin B 12. Vitamin B12 is an important nutrient that helps deliver oxygen and nutrients to the 10 benefits of taking vitamin b12 injections 1. Improves metabolism and supports weight loss 2. Helps against anxiety and depression 3. Increases red blood cells 4. Healthier hair, skin, and 5 weeks after starting b12 injections : r B12_Deficiency