3 findings behind this formula. Hover a card for the detail and the source.
Oral and under-the-tongue vitamin B12 raised blood B12 and lowered homocysteine as effectively as injections.
Systematic review and meta-analysis of 16 studies (6,098 people). B12 raised serum cobalamin by about 403 pg/mL and lowered homocysteine by 4.8 µmol/L, with no significant difference between oral, sublingual and injected routes.
In people low in vitamin B12, high-dose oral B12 normalised blood levels about as well as injections.
Cochrane review of 3 RCTs (153 participants, 3-4 months) comparing oral with injected B12. Oral B12 had similar effects on normalising serum B12; one trial using 2000 mcg/day found higher levels with oral.
In adults low in vitamin B12, 500 mcg taken under the tongue or swallowed raised blood levels equally within 4 weeks.
Randomised study in 30 people with low serum B12 given 500 mcg cobalamin sublingually, orally, or as a B-complex. Serum B12 rose from about 94-108 to 286-293 pmol/L in all groups after 4 weeks, with no difference between routes.