Myth-buster
Anemic children given vitamin B12 shots saw hemoglobin jump by 2.7 g/dL versus 0.5 on oral pills — but the only trial behind that comparison had just one relevant group and was low quality.
This single small study in hospitalized children suggests injected B12 might work faster than oral for severe deficiency, but the evidence is far too thin to change how you or your doctor think about B12 supplementation for the general population.
In one low-quality trial lasting three months, children with B12 deficiency anemia who received a B12 shot had much bigger increases in hemoglobin (a measure of oxygen-carrying red blood cells) than those given oral B12. However, this is the only study indexed on this specific comparison and it had serious limitations, so no reliable conclusion can be drawn yet — the findings are a signal for more research, not a reason to switch from pills to shots.
Where this fits in the evidence
This is among the first studies we've indexed on Vitamin B12 for Increased Hemoglobin Levels — treat it as an early signal until more research accumulates.
The study
- Systematic Review
- 2025-02-18
- Nutrition reviews
- PubMed: 39964959
- DOI: 10.1093/nutrit/nuae227
- Full study breakdown →
This is a plain-language summary of a research finding, not medical advice. Pillser surfaces research signals to help you decide what's worth investigating — always consult a qualified professional before changing what you take.