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San Jose, CA
A 33-year-old female asked:

if you have a vitamin b12 deficiency how long does it take to replenish it with over the counter supplements?

2 doctor answers2 doctors weighed in
Dr. Jaiprakash Thakor Jairam
Specializes in Healthcare Professional
Depend on dosage: The quickest way to replenish B12 would be intra-muscular injections.Should you choose the OTC route,which will be oral,note that absorption(or not) of B12 is probably the most common cause of deficiency.Hence ,you will need a supplement containing very high doses of B12.say 2000ug /pill.If available ,the sublingual form should also be effective as it bypasses gastric influences.
Dr. Daniel Ziegler
Emergency Medicine 30 years experience
Depends: Depends on why you have a B12 deficiency in the first place. Some people, either from gastric bypass surgery or other reasons dont produce intrinsic factor which is made in the stomach and is necessary for us to absorb B12 that we have taken orally. In those cases it takes a shot. In any case 1% of oral B12 is passively absorbed. Once absorbed our bodies are efficient replenishing and storing it.

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Last updated Jun 29, 2019
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