where is b12 injection given Shots vs. IV Infusions: What the difference? Vitamin B12 Shot | IV

These treatments impose substantial physiological stress and often come with side effects incompatible with fasting

For example, MIT spinout Portal Instruments landed a commercialisation deal in 2017 for a smart, needle-free injection device based on technology that could reduce the pain and anxiety associated with needle injections, shorten administration time, and improve patient adherence [53]

May 2008;99(5):945-51

Modern diets, stress, gut issues, and even medications like metformin or antacids can interfere with B12 absorption leaving your body depleted, even if your blood test is normal. What does B12 deficiency feel like

The net effect: adipocytes become metabolically sluggish, oxidizing less fat, storing more energy, and resisting signals that would normally promote energy expenditure