B12 Injections vs. Oral Supplements: Which Works Better? Staying healthy this time of year starts at the cellular level, and B12 plays a major role., Vitamin B12 supports energy production, nervous system function, red blood cell formation, and immune Vitamin B12 injections for MTHFR: Injection or sublingual B12? Methyl Life Supplements 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