3 findings behind this formula. Hover a card for the detail and the source.
Oral, sublingual and injected vitamin B12 all effectively raised blood B12 levels in people with deficiency.
Systematic review and network meta-analysis of 13 comparative studies with 4,275 patients. All three routes increased vitamin B12 levels, with no significant difference between them.
Oral vitamin B12 normalised blood B12 levels as well as injections in people with deficiency, at lower cost.
Cochrane review of three RCTs (153 people) using 1,000-2,000 µg/day orally for 3-4 months. Oral and injected B12 had similar effects on serum B12, and one trial found 2,000 µg/day oral gave higher levels.
Sublingual vitamin B12 at 50 µg a day restored adequate B12 status in vegans and vegetarians with marginal deficiency.
Randomised, double-blind 12-week trial in 40 vegans and vegetarians with marginal deficiency. Both 350 µg/week and 2,000 µg/week sublingual B12 raised serum B12 and holotranscobalamin and lowered homocysteine and methylmalonic acid.