Calcium

Calcium

Best for

Build stronger bones in growing kids

Likely strong benefit · 807–850 mg/day for 48 weeks · 1 meta-analysis , n=728

49 papers · 12 claims · 87 outcomes scored · 7 positive

Outcomes

What calcium actually does, by outcome

Each row is one outcome with effect size, evidence base, the dose that worked in trials, and time to first effect. Magnitude tiers come from native-unit MCID where available, Cohen's d otherwise.

Outcome Effect Evidence Dose Weeks Rank
Build stronger bones in growing kids Likely strong benefit
large
2 meta-analyses n=728 Meta-analyzed 807–850 mg 48 wk
Raise vitamin D levels Large effect, needs confirmation
large
2 RCTs n=40 500 mg 8 wk #2/2
Replenish immune fuel during TB treatment Large effect, needs confirmation
large
2 RCTs n=40 500 mg 8 wk #2/2
Lower fracture risk in older adults Proven benefit
moderate
3 meta-analyses n=135k Meta-analyzed 500–1600 mg #2/3
Build and maintain bone density Likely benefit
moderate
7 meta-analyses n=6.0k Meta-analyzed 250–3320 mg 19–104 wk #1/9
Raise calcium when blood levels run low Faint early signal
small
1 RCT n=20 500–1800 mg 52 wk #1/4
Lower your blood pressure Proven but unnoticeable
trivial
11 meta-analyses n=6.9k Meta-analyzed 500–2000 mg 12–104 wk #8/81
Improve overall diet quality Not enough research
1 meta-analysis n=— Meta-analyzed
Strengthen bones by favoring buildup Not enough research
1 RCT n=— 1200–1800 mg 52 wk
Reduce kidney stone risk Not enough research
2 meta-analyses n=— Meta-analyzed 500–1800 mg 10–104 wk
Raise key nutrient levels in pregnancy Not enough research
2 meta-analyses n=— Meta-analyzed 1500 mg 19–104 wk
Protect bones while breastfeeding Doesn't appear to help
trivial
3 meta-analyses n=1.4k Meta-analyzed 250–3320 mg 19–104 wk

Risk profile

Adverse events and known drug interactions

Safety events

hypocalcemia severe
cardiovascular events severe
kidney stones severe
acute gastrointestinal symptoms requiring hospital admission severe
HELLP syndrome severe
serious adverse event - hip fracture severe
endometrial cancer severe
constipation moderate

Drug interactions

Esomeprazole major decreases concentration
Hydrochlorothiazide major increases toxicity
Semaglutide major decreases concentration
Diuretics major increases effect
Lithium major increases effect
Ciprofloxacin moderate decreases concentration
Metformin moderate decreases effect

Co-studied with

Supplements that share evidence with calcium

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