Browse all articles

Home Get the app
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 · 11 claims · 86 outcomes scored · 6 positive

Evidence summary

Evidence summary

Likely strong benefit

Calcium improves bone mineral density and fracture-related outcomes in growing children and other low-intake groups, with the clearest benefit when dietary calcium starts below target.

  • Across 2 studies (n=728), calcium increased bone mineral density in children across 12 endpoints.2
  • The research footprint spans 49 papers and 86 outcomes, with bone health dominating the evidence base.
  • Benefits are clearest when dietary calcium starts low; extra pills add less value and kidney-stone caution matters.

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.

Build stronger bones in growing kids Likely strong benefit

Children lay down more bone mass during the years that matter most.

2 meta-analyses n=728 807–850 mg 48 wk
33499250·9077538
Raise vitamin D levels Large effect, needs confirmation

Closes the deficiency gap most people don't know they have.

2 RCTs n=40 500 mg 8 wk #2/2
34447494·41924221
Replenish immune fuel during TB treatment Large effect, needs confirmation

Restores a nutrient the immune system burns through faster during active TB.

2 RCTs n=40 500 mg 8 wk #2/2
34447494·41924221
Lower fracture risk in older adults Proven benefit

Fewer hip, spine, forearm, and other fractures from weakened bones.

3 meta-analyses n=135k 500–1600 mg — #2/3
26420387·29279934·31619412
Build and maintain bone density Likely benefit

Keeps mineral packed tightly into hip, spine, and whole-body bone.

7 meta-analyses n=6.0k 250–3320 mg 19–104 wk #1/8
16980314·20579848·25511814·26420598 +3 more
Raise calcium when blood levels run low Faint early signal

Restores a mineral your muscles, nerves, and bones rely on every second.

1 RCT n=20 500–1800 mg 52 wk #1/4
41924221
Improve overall diet quality Not enough research

You naturally gravitate toward more fiber, better fats, and less junk.

1 meta-analysis n=— — —
33499250
Strengthen bones by favoring buildup Not enough research

Your skeleton tips toward building bone faster than it breaks down.

1 RCT n=— 1200–1800 mg 52 wk
25511814
Reduce kidney stone risk Not enough research

Corrects the urine chemistry imbalances that let crystals form.

2 meta-analyses n=— 500–1800 mg 10–104 wk
11271790·33499250
Raise key nutrient levels in pregnancy Not enough research

Gets you to sufficient levels before delivery.

2 meta-analyses n=— 1500 mg 19–104 wk
20554790·33499250
Protect bones while breastfeeding Doesn't appear to help

Keeps your bone mass intact during the mineral drain of lactation.

3 meta-analyses n=1.4k 250–3320 mg 19–104 wk
16980314·20554790·26420598

Forms & standardisation

The best-studied forms are plain calcium salts, especially carbonate and citrate, not fancy blends. On the label, look for the amount of elemental calcium, because that is the number that tells you the real dose.4 If you use acid blockers or have a sensitive stomach, the form matters more than the marketing because carbonate leans on stomach acid while citrate does not.4

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

Vitaminb6 3 shared outcomes · d=0.64
Vitamind 2 shared outcomes · d=0.10

Frequently asked

Common questions

Is calcium better from food or supplements?

Food first wins for most people, because you get calcium in a package with protein and other nutrients. Supplements make sense when your diet leaves you short or when you need a precise daily dose.4

Should you take calcium with vitamin D?

They pair well when you are low in both, and the biggest fracture trial in older adults used calcium plus vitamin D every day.1

What type of calcium supplement works best?

Calcium carbonate gives you more calcium per pill and fits best with meals. Calcium citrate is easier if you want flexibility or take acid-reducing medicine.4

Can calcium supplements cause kidney stones?

High supplemental calcium raises stone risk in some people, especially if you already have a stone history. If that is you, do not guess at the dose.4

Track calcium in the app

Log doses, check interactions, compare it to alternatives — all backed by the same evidence base.

One email when we launch. No spam, no selling.

Sources

  1. 1. Calcium plus vitamin D supplementation and the risk of fractures (2006) ↑
  2. 2. Calcium supplementation and bone mineral density in children: a systematic review and meta-analysis
  3. 3. Calcium supplementation and bone loss in postmenopausal women: a meta-analysis
  4. 4. Calcium - Health Professional Fact Sheet

Generated May 15, 2026

Want personalized recommendations?

Show me what works for me