Supplement
Calcium
An essential mineral whose supplement case survives only where intake is genuinely low.
Calcium is the body's main structural mineral for bone and teeth, and a signaling mineral for nerves and muscle. We grade Calcium C+ on evidence and C+ for worth-it at about $4-9 per month.
Evidence
Worth it
Typical cost: $4-9/month
What it does
Calcium is the body's main structural mineral for bone and teeth, and a signaling mineral for nerves and muscle. As a supplement it is sold as carbonate or citrate to close the gap between dietary intake and the 1,000 to 1,200 mg daily target, most often for bone protection after menopause.
What the research says
Supports bone health where intake is low, especially with vitamin D in institutionalized or deficient older adults
Evidence: moderate. The clearest positive tradition is in deficient, institutionalized elderly given calcium with vitamin D. Outside that setting, the supplement evidence thins out fast (see the null below).
No demonstrated fracture reduction in community-dwelling adults taking it on their own
Evidence: moderate. The Women's Health Initiative calcium/vitamin D trial (36,282 postmenopausal women, 7 years) found no significant hip-fracture reduction overall (HR 0.88, CI 0.72 to 1.08); women who took at least 80 percent of doses showed a benefit (HR 0.71), a subgroup reading. A 2017 JAMA meta-analysis of community-dwelling older adults found no association with lower fracture risk at all.
Against routine low-dose use for fracture prevention (USPSTF)
Evidence: strong. The US Preventive Services Task Force (2018) recommends against daily supplementation with 1,000 mg or less of calcium (with 400 IU or less of vitamin D) for primary fracture prevention in community-dwelling postmenopausal women, and finds the evidence insufficient for other groups and doses.
An essential mineral with a surprisingly weak supplement record. The flagship trial was null on fractures for the average community-dwelling woman who takes it, the biggest meta-analysis of community-dwelling older adults found no fracture association, and the USPSTF recommends against the routine low-dose use case outright. What survives grading is narrower: benefit where intake is genuinely low, most clearly in institutionalized or deficient older adults, usually alongside vitamin D. A proposed cardiovascular harm signal (the Bolland meta-analyses) remains contested and is recorded in the safety notes rather than the grade.
The week's longevity and biohacking news.
This grade for Calcium rests on the record above. When a new result changes that record, the grade changes with it, and the Thursday email is where the change lands first: the week's longevity and biohacking news, in plain English, linked back to the reasoning on this page.
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Every grade follows a published rubric, and sponsors never change one. When the evidence moves a grade, Thursday is where you hear it first, before you renew a stack that stopped earning its cost.
Is it worth it?
Evidence (C+) sits below the leaderboard floor, so the worth-it grade is capped at C+ however inexpensive it is. About $6 a month at a common dose. Derived from the October 2026 worth-it model.
Typical cost
$4-9/month
Common form, not a brand recommendation
Dosage context established
Daily requirement is about 1,000 to 1,200 mg of elemental calcium from all sources, and food counts first: most adults in the US already get 700 to 900 mg from diet. Where a supplement is used, absorption caps at roughly 500 mg of elemental calcium per dose, so split doses beat one large one. Carbonate (40 percent elemental) needs food; citrate (21 percent) does not. The upper limit is 2,000 to 2,500 mg/day total depending on age; more is not better and raises the stone risk below.
Worth-it leaderboard
Calcium sits outside the worth-it top 20.
Calcium sits outside the current top 20 on the gated leaderboard. The leaders below clear an evidence floor of B- before price counts at all, so cheap alone never earns a rank.
See the full worth-it leaderboard →
When the evidence moves a grade, this ranking moves with it. Thursday is where you hear it first.
Safety notes
Kidney stones are the established harm: the Women's Health Initiative trial found a 17 percent higher stone risk on calcium plus vitamin D (HR 1.17). A cardiovascular signal was proposed in meta-analyses by Bolland and colleagues (2010 to 2011, suggesting higher myocardial infarction risk); later analyses and specialty-society reviews found no consistent harm at typical intakes, so the question is contested, not settled. Calcium binds several medicines and minerals and blocks their absorption: take it hours apart from iron, levothyroxine, tetracycline and fluoroquinolone antibiotics, and bisphosphonates. Combined intake from food plus supplements above the upper limit (2,000 to 2,500 mg/day) is where the documented problems concentrate.
Longevity Lab Report
Calcium news. Graded when it happens.
The grade on this page stays free. The email carries the news on calcium: expert moves, dose changes, and what is working, in plain English every Thursday.
Changelog
Last updated 2026-10-23
- 2026-10-23|Graded from the Women's Health Initiative calcium and vitamin D trial, the 2017 JAMA fracture meta-analysis, and the USPSTF's 2018 recommendation against routine low-dose supplementation for fracture prevention in community-dwelling postmenopausal women.
- 2026-10-23|Listed under longevity for its bone-health findings in older adults; the library has no bone-specific goal, and the graded record, not the goal tag, carries the setting limits (deficient and institutionalized adults are where the positive evidence lives).