If you're a vegan, and don't have any digestive issues to suggest problems with absorption, you can just take oral B12, at least 1,000 mcg/d and probably a higher dose would be safer (often available as 5,000 mcg tablets.) Methylcobalamin is better for people who have genetic issues with not being able to methylate well. Sublingual B12 may be better for people who take acid blockers or have low stomach acid or absorption problems; shots or B12 patches may be needed for people with big issues with absorption or neurological disease related to B12 deficiency.
