Calcium (carbonate vs citrate) and bones & joints
What 8 graded rows on calcium (carbonate vs citrate) agree on for bones & joints, and where they differ. Counted side by side, never averaged.
Consensus finder Rows from the Calcium (carbonate vs citrate) page, reviewed Oct 21, 2026 How it decides
What the rows agree on
Each block and row is one graded row from the Calcium (carbonate vs citrate) page, with its PubMed record.
Your question
Calcium (carbonate vs citrate) and bones & joints
8 rows · 198,413 peopleSplit. 5 rows found an improvement, 2 found no difference and 1 found a worse outcome.
- AGrade A× 1
- BGrade B× 3
- CGrade C× 2
- ∅No effect× 2
- Rows
- 8
- Trials
- 8
- At least: a review without a trial count
- People
- 198,413
- Pooled reviews may count some twice
Where they differ
From the rowsThe best-graded row, grade A, is a meta-analysis of 12,257 people (2015) and found an improvement. 2 rows are graded No effect, our grade for adequately powered trials that found no effect.
The 2 rows that found no difference were larger: a median of 30,106 people, against a median of 12,257 people for the 5 rows that found an improvement.
Only the 5 rows that found an improvement name children or teens in their population.
The rows
5 improved · 2 no difference · 1 worse- AGrade ABone mineral density in adults over 50 · Improved
Meta-analysis · n 12,257 · 2015 · Adults over 50 in 51 randomized trials of calcium supplements (with or without vitamin D)
Effects were similar for doses of ≥1000 vs <1000 mg/day and ≤500 vs >500 mg/day · 1 to more than 2 years
Supplements increased bone mineral density by 0.7-1.8% at all five skeletal sites, but the gain did not grow after the first year. The authors judged the increases unlikely to meaningfully lower fracture risk.
Row on the Calcium (carbonate vs citrate) page · PubMed 26420598 (opens PubMed)
- BGrade BFractures with calcium plus vitamin D (including institutionalized adults) · Improved
Meta-analysis · n 30,970 · 2016 · Community-dwelling and institutionalized middle-aged to older adults in 8 randomized trials
Calcium plus vitamin D; doses varied across trials · Varied across trials
Total fractures were 15% lower (SRRE 0.85; 95% CI 0.73-0.98) and hip fractures 30% lower (SRRE 0.70; 95% CI 0.56-0.87).
Row on the Calcium (carbonate vs citrate) page · PubMed 26510847 (opens PubMed)
- BGrade BBone density in people 35 or younger · Improved
Meta-analysis · n 7,382 · 2022 · Children, adolescents and adults up to 35 years in 43 randomized trials
Doses varied across trials · Varied across trials
Bone density rose at the femoral neck (SMD 0.627; 95% CI 0.338 to 0.915) and total body (SMD 0.330), with no effect on total-hip or lumbar-spine bone density. Femoral-neck gains were larger at ages 20–35 than under 20.
Row on the Calcium (carbonate vs citrate) page · PubMed 36164828 (opens PubMed)
- CGrade CAny fracture with calcium plus vitamin D · Improved
Meta-analysis · n 51,126 · 2026 · Adults not on osteoporosis drugs, mostly community dwelling (15 combined-supplement trials within a 69-trial review)
Doses varied across trials · Varied across trials
Any fracture was 9% lower (RR 0.91; 95% CI 0.84 to 0.99; high certainty), but the authors judged the absolute risk reduction below the threshold they considered clinically meaningful and found little to no effect on other fracture and fall outcomes.
Row on the Calcium (carbonate vs citrate) page · PubMed 42161415 (opens PubMed)
- CGrade CCalcium absorption: citrate vs carbonate · Improved
Meta-analysis · n 184 · 1999 · 15 absorption studies, fasting or with meals
Single test doses; amounts varied by study · Single-dose absorption studies
Absorption from citrate was higher than from carbonate by 20.0% overall, 27.2% on an empty stomach and 21.6% with meals.
Row on the Calcium (carbonate vs citrate) page · PubMed 11329115 (opens PubMed)
- ∅No effectFractures in community-dwelling older adults (calcium, vitamin D or both) · No difference
Meta-analysis · n 51,145 · 2017 · Community-dwelling adults older than 50 in 33 randomized trials
Varied across trials · Varied across trials
No significant link with hip fracture for calcium (RR 1.53; 95% CI 0.97 to 2.42) or calcium plus vitamin D (RR 1.09; 95% CI 0.85 to 1.39), and none for nonvertebral, vertebral or total fractures, regardless of dose, sex or baseline intake.
Row on the Calcium (carbonate vs citrate) page · PubMed 29279934 (opens PubMed)
- ∅No effectAny fracture with calcium alone · No difference
Meta-analysis · n 9,067 · 2026 · Adults not on osteoporosis drugs, mostly community dwelling and not at high fracture risk (11 calcium-only trials within a 69-trial review)
Doses varied across trials · Varied across trials
Little to no effect on any fracture (RR 0.91; 95% CI 0.81 to 1.01; moderate certainty), and little to no effect on hip, non-vertebral or vertebral fractures or falls.
Row on the Calcium (carbonate vs citrate) page · PubMed 42161415 (opens PubMed)
- BGrade BUrinary stone reports with calcium plus vitamin D · Worse
RCT · n 36,282 · 2011 · Postmenopausal women aged 50-79 in the Women's Health Initiative
1000 mg calcium plus 400 IU vitamin D3 daily (500 mg + 200 IU twice daily) · Average 7.0 years
Self-reported urinary tract stones were 17% more common with supplements (HR 1.17; 95% CI 1.02 to 1.34): 449 vs 381 women.
Row on the Calcium (carbonate vs citrate) page · PubMed 21525191 (opens PubMed)