Major minerals

Calcium

Bone · muscle

Bone mineralization, muscle contraction, neuronal signaling.

Daily target

1300 mg

FDA Daily Value

Upper limit

2500 mg

Tolerable Upper Intake

Catalog matches

supplements in our catalog

Upper-limit caution

The Tolerable Upper Intake Level for Calcium is 2500 mg per day. Routine intakes above this level — counting food + supplements — raise the risk of adverse effects. Multivitamins, fortified foods, and standalone supplements stack faster than people expect.

What Calcium does

Calcium is the most abundant mineral in the body — 99% sits in bone as hydroxyapatite, the remaining 1% drives muscle contraction, nerve signaling, and blood clotting. Serum calcium is held in a narrow range by parathyroid hormone, vitamin D, and calcitonin; when intake falls, the body pulls from bone to defend serum levels. Most adults can hit the RDA from food (dairy, leafy greens, fortified foods); routine supplementation above modest doses has been associated in some meta-analyses with cardiovascular risk, so total intake (food + supplements) is what matters.

Food sources of Calcium

Approximate Calcium content per serving. Whole-food intake counts toward your daily total alongside any supplemental dose.

Food	Serving	Calcium
Plain yogurt	1 cup	450 mg
Milk	1 cup	300 mg
Tofu (calcium-set)	1/2 cup	430 mg
Canned sardines (with bones)	3 oz	325 mg
Cooked collard greens	1 cup	270 mg
Fortified plant milk	1 cup	300 mg

Signs of Calcium deficiency

●Long-term: low bone density, osteoporosis, fragility fractures
●Muscle cramps, twitching, numbness around the mouth (acute hypocalcemia)
●Severe: tetany, seizures, cardiac arrhythmias
●Children: rickets if combined with vitamin D deficiency

Who needs more Calcium

Groups and situations where Calcium requirements rise or status commonly runs low:

●Postmenopausal women — estrogen loss accelerates bone resorption
●Adults over 70 — RDA rises to 1,200 mg
●Lactose intolerance or dairy avoidance without fortified replacements
●Long-term corticosteroid, anticonvulsant, or PPI use
●Inflammatory bowel disease, celiac, post-bariatric

Forms to avoid

Not all Calcium forms absorb equally well. The following forms are commonly used because they're cheap, but their bioavailability is materially lower than alternatives — watch for them on supplement labels:

carbonate

Formulate's product scoring penalizes these forms when they appear as the primary Calcium source — see the methodology page for the rubric.

How Calcium appears on labels

Supplement labels list Calcium under several names depending on the chemical form used. Any of these on an ingredients panel counts toward your Calcium intake:

calcium
calcium carbonate
calcium citrate
calcium malate
calcium hydroxyapatite

Best supplements for Calcium

Top-scoring supplements in our catalog that list Calcium on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.

Thorne

Protein Isolate - Chocolate

Transparent Labs

Grass-Fed Whey Protein Isolate

Thorne

Whey Protein Isolate - Vanilla

Nutricost

Calcium + Vitamin D3 Tablets

Nutricost

Calcium Citrate + Vitamin D

Thorne

Calcium

Thorne

MediClear-SGS™ - Vanilla

Thorne

Calcium-Magnesium Malate

Deep dive

For mechanism of action, dosing protocols, evidence grade, and interaction warnings on Calcium, see the full encyclopedia entry:

Calcium encyclopedia entry →

Research on Calcium

Peer-reviewed studies in our research database that reference Calcium. Each entry links to a detailed methodology review.

Frequently asked questions

What is the daily target for Calcium?

The fda daily value for Calcium is 1300 mg per day for adults. The Tolerable Upper Intake Level is 2500 mg/day from food and supplements combined.

What foods are highest in Calcium?

Plain yogurt (450 mg per 1 cup); Milk (300 mg per 1 cup); Tofu (calcium-set) (430 mg per 1/2 cup). See the food sources section below for the full list.

What is the best form of Calcium to supplement?

Calcium citrate absorbs equally well with or without food and is preferred for older adults on PPIs. Calcium carbonate is cheaper but needs stomach acid to absorb — take with meals. Avoid single doses above 500 mg of elemental calcium; absorption efficiency drops sharply. Pair with vitamin D for full benefit.

What are the signs of Calcium deficiency?

Long-term: low bone density, osteoporosis, fragility fractures; Muscle cramps, twitching, numbness around the mouth (acute hypocalcemia); Severe: tetany, seizures, cardiac arrhythmias.

Who is most at risk for low Calcium?

Postmenopausal women — estrogen loss accelerates bone resorption; Adults over 70 — RDA rises to 1,200 mg; Lactose intolerance or dairy avoidance without fortified replacements.

Related major minerals

Track your full intake

Formulate's free web app aggregates Calcium (and ~40 other nutrients) across every supplement in your stack — flagging underdoses, overlaps, and upper-limit overshoots in one view.

Track your intake free →

Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Targets and upper limits are general adult reference values; individual needs vary by age, sex, pregnancy status, and clinical context.