I took vitamin b12 1000mcg on may 28th how long does it take for b12 too get out of the body fully so I can take a Lower dose 250mcg.

Wrong question. Why ask this? There is no toxic dose of B12. You will absorb only a tiny fraction of these very large doses. Why are you taking it? Most of the time 250 will be about the same as 1000. You can take the 250mcg any time.Since this is in many foods and is even produced by intestinal bacteria, a clinical deficiency occurs only in special circumstances. Vegan diet. Long term use of PPI or H2 blocker s.