b12 where to inject How self-inject intramuscular vitamin - Overview Choosing the Right Needle and
Description
B12 supports normal energy metabolism and red blood cell production, so correcting a genuine deficiency can help you feel and perform like yourself again, but shots are not a proven performance enhancer for people who are not deficient

The technical record

In the United States, injectable B12 is technically a prescription medication

Importantly, it achieves these effects without impacting blood sugar levels or insulin sensitivity
