Calcium

Also known as: calcium citrate, calcium carbonate

Grade A — Strong Evidencemineralfoundational

Recommended Dosage

500–1000 mg

With meals, split doses (citrate form better absorbed)

Essential for bone health, but food sources preferred. If supplementing, always pair with Vitamin D3 and K2.

💪Muscle & Recovery
Last reviewed: 2026-03-09

Evidence Rating: Grade A — Strong Evidence

Multiple high-quality RCTs, systematic reviews, or meta-analyses with consistent findings.

Forms Comparison

Calcium Citrate

✓ High Absorption

Better absorbed than carbonate. Can be taken with or without food. Preferred form.

general supplementationlow stomach acid

Calcium Carbonate

~ Moderate Absorption

Cheapest and most common form. Must be taken with food for adequate absorption. Contains most elemental calcium per pill.

budgetwith meals

Calcium Hydroxyapatite (MCHC)

✓ High Absorption

Derived from bone. Contains additional bone-building minerals. Most expensive.

bone healthosteoporosis prevention

Interaction Warnings

IronModerate

Inhibits iron absorption — take at different times

Thyroid medicationsModerate

Reduces levothyroxine absorption

BisphosphonatesModerate

Take separately by 30+ minutes

⚠️ Important Notes

  • Get from food first if possible
  • Always combine with Vitamin D3 and K2
  • Excess supplementation linked to cardiovascular concerns

Clinical Evidence (1 study)

Calcium intake and bone mineral density

Tai V et al. (2015) — BMJ

Supplementation modestly increases BMD at all sites

View on PubMed

Related Supplements

Zinc

Grade A — Strong Evidence

Essential mineral for immune function, wound healing, and testosterone production. Lozenges reduce cold duration by ~33%.

Magnesium Glycinate

Grade A — Strong Evidence

Highly bioavailable form of magnesium. Strong evidence for sleep quality, muscle relaxation, and stress reduction. Most adults are deficient.

Vitamin D3

Grade A — Strong Evidence

Essential hormone precursor. Most people in northern latitudes are deficient. Strong evidence for immunity, bone health, and mood.

Boron

Grade C — Preliminary

Trace mineral that supports calcium metabolism, vitamin D utilization, and potentially testosterone levels.

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⚕️ Important Disclaimer

This information is for educational purposes only. It is not medical advice. Always consult a healthcare provider before starting any supplement regimen, especially if you take medications or have health conditions.

Evidence Stack does not sell supplements and has no affiliate relationships with supplement manufacturers.