Harvard Men's Health Watch

Ask the doctor: B12 shots vs. pills

Q. I am 72 years old and was recently diagnosed with B12 deficiency. Which is better—the B12 pill or the shot?

A. Low B12 can cause anemia and fatigue. For many people with low B12 levels, a daily supplement in the form of a pill is as effective as taking a monthly muscle injection. The choice of shot or pill depends on the reason for the deficiency.

Vitamin B12, found in any food from animals, needs to be released from proteins during digestion. If the stomach does not produce enough acid, the body does not absorb B12 from food very well, but it can still easily absorb the B12 in an oral supplement.

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