injection de b12 Injection: Uses, How to Take It & Side Effects Two B12 vitamin injection vials

Metformin: This diabetes medication might impair vitamin B12 absorption in some people

J Clin Invest 90 : 23482354 Biolo G et al

[6] [3] [10] A mild deficiency may not cause any discernible symptoms, but moderate deficiency can cause various symptoms, such as feeling tired, lightheadedness, headaches, cold intolerance, pale skin, sore tongue, upset stomach, loss of appetite, hair and skin color changes, numbness or tingling (pins and needles) of the fingers and toes, and tinnitus, and vision, cognitive or psychological problems

Side effects are generally mild or absent

I wonder how our bodies decide what is excess and what is not