Scientific American presents Nutrition Diva by Quick & Dirty Tips. Scientific American and Quick & Dirty Tips are both Macmillan companies.

Q. Getting B-12 injections seems to be a hot new fad. Can B-12 shots really boost your energy? Are they safe? Could you get the same benefit from an oral supplement?

A. Taking B-12 can definitely help boost your energy if you have a B-12 deficiency. Fatigue is a common side effect of B-12 deficiency. And injections are more effective than oral supplements for people whose bodies don’t manufacture “intrinsic factor” because this substance is required for absorption of the nutrient through the digestive tract.

The real question is how many of the starlets and reality show stars who swear by their weekly B-12 shots are actually deficient in B-12 and unable to manufacture intrinsic factor? My guess is very, very few.

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