Therefore, if you have recently changed your diet, become vegan, and stopped consuming B12-rich foods, it may take several years for a deficiency to become apparent, and dietary supplementation might be an adequate solution over any need for B12 injections
it exists to serve patients with documented needs that commercially available drugs cannot meet
"Photoselective vaporization of the prostate with the 180-W XPS-Greenlight laser: Five-year experience of safety, efficiency, and functional outcomes"
Check the labels on breakfast cereals , nutritional yeast , and plant-based milks (like soy or almond) for added B12
These hypothetical mechanisms are amenable to experimental verification
The following table summarizes the evidence landscape honestly, tier by tier