oral vs injected b12 Injections Supplements: Which are more effective? Vitamin B12 Injections vs. Supplements:
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Bibcode:1977Sci...196.1410E

It is also worth seeking advice if you follow a vegan or vegetarian diet, take medications that may affect B12 absorption, or have a digestive condition that may increase your risk of deficiency

Vitamin B12 itself is a water-soluble vitamin your body uses to make red blood cells, keep the nervous system healthy and release energy from food

These can be itchy and able to spread to other parts of the body
