Mineral
Calcium
Also known as: Ca, Calcium ion
Essential mineral for bone health, muscle function, nerve signaling, and blood clotting.
Daily target & upper limit
1300 mg / day · UL 2500 mgCalcium has an established daily reference intake. See best forms, label synonyms, upper-limit warnings, and top-scoring supplements:
Calcium dosage reference →Primary uses
- Bone health
- Muscle function
- Nerve signaling
How it works
- Structural component of bones/teeth
- Required for muscle contraction
- Nerve impulse transmission
Dosage
- Typical range
- 500-1200mg daily
- Timing
- Divided doses
- With food
- Carbonate yes, citrate optional
- Duration
- Long-term
- Special populations
- Post-menopausal women
Forms
- Citrate
- Carbonate
Safety
Common side effects
- Constipation
- Gas
Contraindications
- Hypercalcemia
Products containing 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.
Known interactions
- Warningwith iron
Calcium significantly reduces iron absorption
- Cautionwith magnesium
High calcium can impair magnesium absorption
- Cautionwith zinc
Calcium may reduce zinc absorption
- Synergywith vitamin d
Vitamin D enhances calcium absorption
- Infowith antacids
Antacids reduce calcium absorption
- Warningwith thyroid medication
Calcium blocks thyroid medication absorption
Evidence notes
Essential mineral with strong evidence for bone health
Grade A: Multiple well-designed human trials support the main claims.
Cited research for Calcium
Clinical studies referenced across Formulate guides that mention calcium. Each links to the full study page with PubMed source + the guides that cite it.
- Bolland et al. (2015)BMJ
Calcium intake and risk of fracture: systematic review
- Hurrell R, Egli I (2010)American Journal of Clinical Nutrition
Iron bioavailability and dietary reference values
- Hallberg and Hulthén (2000)American Journal of Clinical Nutrition
Prediction of dietary iron absorption: an algorithm for calculating absorption and bioavailability
Related in Mineral
Check a full stack
Formulate's free interaction checker lets you paste in any combination of supplements and medications at once — every pairing flags severity, timing, and cited evidence.
Open the checkerMedical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider.