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
Calcium benefits: where the science stands
For bone: no.
Bone is what most people take calcium for, and the strongest evidence says it does not help: a combined review covering 69 trials found no real difference. As of August 2026, the verdicts on this page rest on evidence from 109 trials, drawn from the strongest research among the 16,364 papers on PubMed that mention calcium. Every claim is checked below.
16,364 papers on PubMed · evidence from 109 trials
Claim by claim
- BoneWell studied, and it does not work. The biggest review covered 69 trials.
- PregnancyThe science is still forming. The best studies disagree.
Pairs people ask about
The three sources we read
- 2025Meta-analysis · pools 6 trials, 15,364 people · no clear effect on pregnancysource
- 2025Meta-analysis · pools 34 trials · moderate benefit for pregnancysource
- 2026Meta-analysis · pools 69 trials, 153,902 people · no clear effect on bonesource
Chosen as the strongest evidence out of 16,364 papers on PubMed. Every row links to its paper.
Fair questions
Does calcium work?+
For bone, the strongest evidence says no. The biggest review covered 69 trials.
Is calcium safe?+
No caution is recorded on this page. That is not a safety guarantee; the studies we read were not safety trials.
Why only 3 sources, when PubMed lists 16,364?+
The 16,364 is every paper that mentions calcium 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 3 cover 109 trials between them, and every one is linked above. Both counts are measured, not estimated.