If a person take vitamin B12 tab of 500mcg orally.On an average how much a person can absorb of it in mcg.Any research on it?
Vitamin B12 tab absorption - Pernicious Anaemi...
Vitamin B12 tab absorption
It would depend on the individual and their particular diagnosis. Some cannot absorb via the gut and so go for sublingual or injection. It would also depend on the formulation to determine bioavailability. Unlike better regulated medicines, supplements tend not to have a detailed package insert where you might find information on the pharmacokinetics of a drug. Hope this is of some use although it doesnt answer your Q.
these are links to some articles on using oral B12 in treating a deficiency caused by malabsorption
ncbi.nlm.nih.gov/pmc/articl...
ncbi.nlm.nih.gov/pmc/articl...
ncbi.nlm.nih.gov/pmc/articl...
people with PA (the most common absorption problem) will, on average absorb 1% of oral B12 - so you would be getting 5mcg a day - which is 1-2x the RDA for B12 depending on where you are based. So, might be okay in maintaining your levels, but unlikely to be particularly good in raising them or giving you the extra B12 that you would need whilst repairing the damage done by a B12 deficiency.
1% is roughly the amount of B12 that is absorbed outside the ileum in general transit through the gut. It is an average and there is, as with most things B12, a lot of variation from person to person - so as a delivery method it works for some people but not for others, and short of trying it, at the moment there isn't a test to see which category you fall into.