Intramuscular (IM) vitamin injections are administered directly into the muscle. This means the vitamin will get absorbed by the muscle and blood vessels directly. Oral vitamins must get broken down by the GI tract (through stomach, intestines) then go through the liver for metabolizing. Anyone who has a poor diet, GI disorder, gut dysbiosis (imbalanced gut microbiome), or gut inflammation will not be able absorb oral vitamins. IM vitamin injections bypass the gut and 90 percent or more of the vitamin is absorbed by the body. Vitamin injections are more bioavailable and the body can utilize them better.