Oral B12 can also work alongside injections
We used data on serum folate and vitamin B-12 concentrations from 4940 NHANES III participants and 5473 NHANES 19992002 participants who were over the age of 20 y
Its also reasonable to check the level if youve been on medication to reduce stomach acid for a long time
Absorption : Because its injected, B12 is absorbed through the muscle/tissue into the bloodstream, bypassing digestion
If the redness expands beyond the circle in subsequent hours, the reaction is progressing and may need medical evaluation
8 Where results are unclear, serum MMA and homocysteine levels (both of which accumulate with B12 deficiency as discussed above) can also be used to confirm a diagnosis, although homocysteine is not specific to B12 deficiency, as it may also be caused by deficiencies in other B vitamins