Mineral
Calcium Citrate
Also known as: Calcium, Calcium citrate, Citracal
Well-absorbed calcium form that doesn't require stomach acid. Better for those on acid-reducing medications.
Last reviewed June 2026 · Evidence graded from peer-reviewed research, not editorial opinion. Educational only — not medical advice.
Daily target & upper limit
1300 mg / day · UL 2500 mgCalcium Citrate has an established daily reference intake. See best forms, label synonyms, upper-limit warnings, and top-scoring supplements:
Calcium Citrate dosage reference →Primary uses
- Bone health
- Muscle function
- Nerve signaling
How it works
- Absorbed without stomach acid
- Good bioavailability
- May be better tolerated
Dosage
- Typical range
- 500-1000 mg daily in divided doses
- Timing
- Any time, divide doses
- With food
- Optional
- Duration
- Safe long-term
- Special populations
- Those on PPIs, older adults
Forms
- Tablet
- Capsule
Safety
Common side effects
- Constipation
- Bloating
Contraindications
- Hypercalcemia
- Kidney stones
Products containing Calcium Citrate
Top-scoring supplements in our catalog that list Calcium Citrate on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.
Known interactions
- Warningwith calcium
Calcium significantly reduces iron absorption
- Cautionwith calcium
High calcium can impair magnesium absorption
- Cautionwith calcium
Calcium may reduce zinc absorption
- Synergywith vitamin d
Vitamin D enhances calcium absorption
- Infowith calcium
Antacids reduce calcium absorption
- Warningwith calcium
Calcium blocks thyroid medication absorption
Evidence notes
Well-absorbed calcium form
Grade A: Multiple well-designed human trials support the main claims.
Cited research for Calcium Citrate
Clinical studies referenced across Formulate guides that mention calcium citrate. 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
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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Individual needs and risks vary — consult a professional before starting, stopping, or combining supplements, especially if you are pregnant or nursing, taking medication, or managing a health condition.