Is Vitamin B12 Injection Better Than Tablets?
For most people with low vitamin B12 levels, oral B12 supplements (tablets) are just as effective as injections for raising blood levels over time.[1, 4, 6, 8] However, injections offer some advantages in specific situations.
- Rapid B12 Needs: If you require a quick increase in B12 levels, injections are absorbed more rapidly than oral supplements.[1, 9] This is because injections deliver B12 directly into the muscle, bypassing the digestive system.[2]
- Malabsorption Issues: Individuals with digestive problems hindering B12 absorption from the gut may benefit more from injections.[1] Oral B12 might not be effectively absorbed in these cases.
When Tablets Are Equally Effective:
- Long-Term Maintenance: For many individuals, daily or weekly oral B12 tablets are as effective as monthly injections in maintaining healthy B12 levels over the long term.[4, 6, 8] Studies have shown equivalent results in normalizing serum B12 levels after a few months.[6] High-dose oral B12 supplements can be just as effective as injections for achieving neurological and hematological responses.[4]
- Convenience & Cost: Oral tablets are generally more convenient and less expensive than regular injections.
Absorption Differences:
Injections achieve a higher and faster absorption rate (15-97%) because the B12 is directly introduced into the bloodstream.[7] Oral B12 absorption, while effective for many, can vary significantly.
In summary, while injections provide faster absorption and are beneficial for those with malabsorption issues, oral B12 tablets are equally effective for the majority of people in achieving and maintaining adequate B12 levels over time. The best option depends on individual needs and circumstances.
