What do the states mean?+
- Solid: well studied, and it works.
- Half-there: the science is still forming.
- A ghost: almost no real studies.
- Hollow: well studied, and it does not work.
- A cord: the pair itself has been tested together.
- Air: nobody has ever tested this pair.
The full scoring method: How we score
Iron benefits: where the science stands
For anaemia and iron levels: yes.
Anaemia and iron levels are what most people take iron for, and the strongest evidence says it helps (a combined review covering 57 trials). As of August 2026, the verdicts on this page rest on evidence from 70 trials, drawn from the strongest research among the 12,426 papers on PubMed that mention iron. Every claim is checked below.
12,426 papers on PubMed · evidence from 70 trials
Claim by claim
- Anaemia and iron levelsWell studied, and it works. The biggest review covered 57 trials.
- Memory and focusThe science is still forming. Results lean positive, but there is not much yet.
Pairs people ask about
The two sources we read
- 2023Meta-analysis · pools 13 trials · moderate benefit for memory and focussource
- 2024Meta-analysis · pools 57 trials, 48,971 people · large benefit for anaemia and iron levelssource
Chosen as the strongest evidence out of 12,426 papers on PubMed. Every row links to its paper.
Fair questions
Does iron work?+
For anaemia and iron levels, yes. The biggest review covered 57 trials.
Is iron safe?+
No caution is recorded on this page. That is not a safety guarantee; the studies we read were not safety trials.
Why only 2 sources, when PubMed lists 12,426?+
The 12,426 is every paper that mentions iron in any way: animal studies, blood measurements, papers where it is a side note. The strongest sources are combined reviews, and each one already gathers every trial its authors could find. Our 2 cover 70 trials between them, and every one is linked above. Both counts are measured, not estimated.