i think you mean micrograms (mcg) instead of milligrams (mg). if you really are taking 105mg that would equal 105 000mcg. the recommended amount of vitamin b12 for adults is 2. 4mcg. but there is no upper limit set by the institute of medicine because no adverse effects have been found with taking excess vitamin b12. because it is a water soluble vitamin it's potential for toxicity is low. most people get enough from diet unless they are vegetarians older or have a health condition that decreases the absorption of vitamin b12. for more on proper dosing and side effects see this webmd page.
is 105 mg of vitamine b12 a dangerous dosage? . i am taking a multivitamin tablet that contains 100 mg with methycobalmin? and 5 mg of b12 as methycobalmin andadenosylcoalmin? am i taking too much daily of this vitamin?