Calcium
Also known as: Calcium Citrate, Calcium Carbonate, Calcium Malate
The body's most abundant mineral — critical for bone density, muscle contraction, and nerve signaling.
What it is
Calcium is the most abundant mineral in the human body, with approximately 99% stored in bones and teeth. It is essential for skeletal integrity, but also plays critical roles in muscle contraction, neurotransmitter release, and blood coagulation. Dietary calcium intake among adults is frequently inadequate, making targeted supplementation particularly relevant for bone health over the lifespan.
How it works
Calcium absorption requires vitamin D for active transport in the small intestine. Bone remodeling requires adequate calcium alongside vitamin K2 (which directs calcium to bone rather than arterial walls), magnesium, and phosphorus. In muscle cells, calcium released from the sarcoplasmic reticulum triggers actin-myosin cross-bridging — the fundamental mechanism of contraction.
Clinical dose range
500–1,200 mg elemental calcium/day
Total daily calcium (diet + supplements combined) should not exceed 2,000–2,500 mg. Supplement doses above 500 mg should be split across two servings for optimal absorption. Calcium carbonate requires stomach acid — take with food.
Forms comparison
What to look for on the label
- Paired with vitamin D3 and K2 for complete bone health support
- Dose per serving ≤500 mg elemental calcium (larger amounts split across servings)
- Third-party tested for heavy metals — calcium is frequently contaminated with lead
- Specifies the calcium compound form on the label
Health goals supported
Safety & dosing notes
Upper limit: 2,000–2,500 mg/day total. Excess calcium from supplements (not food) is associated with increased cardiovascular calcification risk — always pair with K2 MK-7. May interfere with iron and zinc absorption if taken simultaneously.
SuppsBuddy awards bonus scores for calcium products that include vitamin K2 MK-7 for proper bone utilization. Products exceeding 500 mg per serving lose points for absorption efficiency. Lead contamination risk flags third-party testing as a critical marker for calcium specifically.
Frequently asked questions
What is Calcium?
Calcium is the most abundant mineral in the human body, with approximately 99% stored in bones and teeth. It is essential for skeletal integrity, but also plays critical roles in muscle contraction, neurotransmitter release, and blood coagulation. Dietary calcium intake among adults is frequently inadequate, making targeted supplementation particularly relevant for bone health over the lifespan.
How does Calcium work?
Calcium absorption requires vitamin D for active transport in the small intestine. Bone remodeling requires adequate calcium alongside vitamin K2 (which directs calcium to bone rather than arterial walls), magnesium, and phosphorus. In muscle cells, calcium released from the sarcoplasmic reticulum triggers actin-myosin cross-bridging — the fundamental mechanism of contraction.
What is the typical clinical dose range for Calcium?
500–1,200 mg elemental calcium/day. Total daily calcium (diet + supplements combined) should not exceed 2,000–2,500 mg. Supplement doses above 500 mg should be split across two servings for optimal absorption. Calcium carbonate requires stomach acid — take with food.
What forms of Calcium should I look for?
Calcium Citrate: Absorbed with or without food; best for those with low stomach acid or on PPIs | Calcium Malate: Good bioavailability, less constipation risk than carbonate | Calcium Carbonate: High elemental calcium content (40%) but requires stomach acid; take with food | Calcium Phosphate: Adequate bioavailability; naturally occurring in dairy | Calcium Gluconate: Very low elemental calcium (9%) — impractical as a supplement form
Is Calcium safe?
Upper limit: 2,000–2,500 mg/day total. Excess calcium from supplements (not food) is associated with increased cardiovascular calcification risk — always pair with K2 MK-7. May interfere with iron and zinc absorption if taken simultaneously. This information is educational and is not medical advice.
How does SuppsBuddy evaluate Calcium?
SuppsBuddy awards bonus scores for calcium products that include vitamin K2 MK-7 for proper bone utilization. Products exceeding 500 mg per serving lose points for absorption efficiency. Lead contamination risk flags third-party testing as a critical marker for calcium specifically.
Related ingredients
This page is for educational purposes only. These statements have not been evaluated by the FDA. This information is not intended to diagnose, treat, cure, or prevent any disease. Always consult a qualified healthcare professional before starting any supplement.