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San Leandro, CA
A 26-year-old male asked:

is it ok to take 2500 mg b12, 250 mg of magnesium, and a 13.5 gram protein shake one after the other?

1 doctor answer2 doctors weighed in
Dr. Randy Baker
Holistic Medicine 40 years experience
Yes, however...: This is totally safe. However, magnesium (and other minerals) are best absorbed on an empty stomach) so waiting a half hour or so between taking magnesium and the protein shake may enhance absorption. Some forms of magnesium are better absorbed than others- the best-absorbed are taurate, glycinate, malate, aspartate and citrate.
Dr. Gurmukh Singh
Pathology 49 years experience
While it is safe to take 2500 mg of B12, it is entirely useless to overdose yourself so much. The daily requirement for B12 is a few micrograms.
Sep 5, 2015
Dr. Randy Baker
Dr. Randy Baker commented
Holistic Medicine 40 years experience
Provided original answer
Dr. Singh, I agree that there is no need to take that much B12, though it will not cause an "overdose." No matter how much B12 one takes there is a limit to how much can be absorbed but because it is not well-absorbed 1000 mcg is reasonable. See https://chriskresser.com/what-everyone-especially-vegetarians-should-know-about-b12-deficiency/ and http://lpi.oregonstate.edu/mic/vitamins/vitamin-B12
Sep 5, 2015

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