Safety Profile
Overall safety rating: Safe with Caution
Calcium Side Effects & Safety
This content is for informational purposes only and does not constitute medical advice. Consult your healthcare provider before starting any supplement. Full disclaimer
Potential Side Effects
- Constipation (most common, especially with calcium carbonate)
- Bloating and gas
- Potential increased cardiovascular risk at high supplemental doses (>1,000mg/day) — controversial, debated in literature
- Kidney stone risk may increase with high-dose supplements without adequate hydration
Drug & Supplement Interactions
- Reduces absorption of thyroid medications (levothyroxine) — separate by 4 hours
- Reduces absorption of bisphosphonates — separate by 2 hours
- Reduces absorption of tetracycline and quinolone antibiotics
- Competes with iron, zinc, and magnesium for absorption — take at different times
- Vitamin D enhances calcium absorption — always co-supplement
Maximum Dose
Do not exceed: 2,500mg/day total from all sources (NIH UL); do not exceed 500-600mg per dose for optimal absorption
References
- Jackson RD, LaCroix AZ, Gass M, et al. (2006). Calcium plus vitamin D supplementation and the risk of fractures. New England Journal of Medicine. DOI PubMed
- Bolland MJ, Leung W, Tai V, et al. (2015). Calcium intake and risk of fracture: systematic review. BMJ. DOI PubMed
- Tai V, Leung W, Grey A, Reid IR, Bolland MJ (2015). Calcium intake and bone mineral density: systematic review and meta-analysis. BMJ. DOI PubMed