Intramuscular vitamin injections are used as an alternative to oral supplementation if you are significantly deficient or if your gastrointestinal absorption is suboptimal. Vitamins that I commonly inject for patients include vitamin B9, B12 and vitamin D. MIC is another common intramuscular injection that consists of methionine, inositol, choline, and the essential B vitamins (B1, 2, 3, 5, 6, 12). MIC has been shown to support optimal liver function, nervous system function, metabolism and weight loss.