When you get B12 shots, a water soluble vitamin, it increases the metabolism in your cells
Who should consider vitamin b12 Individuals experiencing fatigue, memory lapses, or neurological symptoms may find vitamin B12 injections beneficial
It is an intracellular metabolic-enzyme modulator, which is why its research read-outs are things like NAD+ levels and adipocyte gene expression, not how full you feel. That mechanistic distinction is the single most important thing to understand before looking at any dose number
If you are unsure whether B12 injections are right for you in the first place, that starts with your GP and a blood test, as set out in the NHS treatment pathway
High-dose therapy may also cause a brief increase in blood pressure, though this usually returns to baseline within a few hours