B12 Injections for Weight Loss: Efficacy & Benefits Efficacy of different routes of vitamin B12 supplementation for the treatment of patients with vitamin B12 deficiency: A systematic review and network meta analysis Irish Journal of Medical Science (1971 ) Benefits of a Vitamin B12 Injection Vitamin B12 injections are commonly used for people who are deficient, struggle to absorb B12 from tablets, or require a faster and more effective boost. Vitamin B 12 intramuscular injections are also used therapeutically to help restore energy and combat various symptoms related to such deficiencies. Vitamin B 12 is essential to the development of healthy blood cells, nerve