Calcium
Commonly used for
Healthy AgingHeart HealthBone Health
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What is it? / Overview
Calcium is the primary mineral in bones and teeth and is necessary for muscle contraction and nerve function. Supplementation is most beneficial when dietary intake is insufficient particularly in older adults at risk for osteoporosis.
How is it used? / Administration
Form: Calcium citrate (better absorbed); calcium carbonate with meals if tolerated
Typical dose studied: 500–600 mg per dose to reach 1,000–1,200 mg/day total from diet and supplements
Timing: With meals (carbonate); citrate can be taken anytime
Food sources preferred whenever possible. Divide doses for better absorption.
What does it pair with?
Pairs well with:
Vitamin D is required for the body to actively absorb calcium — Vitamin D is required for active intestinal calcium absorption — without adequate D, calcium absorption drops substantially.
Often taken together, but neither requires the other — Both contribute to bone and neuromuscular physiology, but there's no requirement to supplement them simultaneously.
Best taken separately from:
Calcium can interfere with iron absorption — commonly recommended to take at different times, especially for therapeutic iron doses.
How well does it work? / Evidence
✓ Well-established
Who should avoid it?
Avoid with: Hypercalcemia; Kidney stones / Nephrolithiasis; Hyperparathyroidism
Interacts with: Separate from levothyroxine, iron, tetracyclines, fluoroquinolones, bisphosphonates
Already taking it? Count dietary calcium before supplementing. Divide doses > 500–600 mg.
Research & references
National Osteoporosis Foundation Guidelines. NIH Office of Dietary Supplements: Calcium Fact Sheet. Weaver CM et al. Calcium Plus Vitamin D and Fracture Prevention.
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