Calcium
The mineral that supports bone and dental strength.
Calcium is an essential mineral that contributes to bone and dental mineralization and participates in physiological processes including blood coagulation, muscle contraction, nerve transmission and hormone release. The majority of the body’s calcium is stored in bones and teeth, so a regular dietary intake from foods or supplements is necessary to support normal function.
Supplements are available in several chemical forms (for example calcium carbonate, citrate and hydroxyapatite) and are often combined with vitamin D to aid absorption. Individuals at higher risk of low intake — including post‑menopausal women, people with amenorrhoea, vegans, vegetarians and those with lactose intolerance — may consider supplementation, but needs and effects vary by individual and professional advice is recommended.
At a Glance
An abundant inorganic mineral, calcium forms the primary mineral component of bones and teeth and supports a range of physiological processes across the body. Calcium is involved in blood coagulation, muscle contraction, nerve transmission and hormone release. Dietary sources and supplements help maintain levels, and supplements are commonly available in several salt forms often combined with vitamin D to support absorption.
| Common name |
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| Scientific name | Ca |
| Origin | Widespread in Earth’s crust (limestone, shells) |
| Parts used | Inorganic mineral |
| Active compounds |
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| Main benefits |
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| Available forms |
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Origin & History
Calcium is an abundant mineral in the Earth’s crust, most commonly present as calcium carbonate in limestone, shells and other sedimentary deposits; it is not found in a pure metallic state in nature. The element (symbol Ca, atomic number 20) occurs widely in soils, rocks and marine materials, and in living organisms where an adult typically contains about 1 to 1.2 kg, mostly concentrated in bones and teeth.
Materials derived from calcium have been used across cultures for millennia in construction and daily life. Lime and calcium‑rich mortars were a key component of Roman engineering, used to build aqueducts, temples and roads that have endured for centuries. Calcium‑containing substances have also been applied in agriculture and craft traditions, while calcium‑rich foods such as dairy, certain leafy vegetables and small‑bone fish have featured in traditional diets worldwide.
Composition & Active Compounds
Calcium is typically encountered in nature as mineral salts rather than the pure metal, commonly forming white or colorless solids such as calcium carbonate in limestone, shells and bone; supplement preparations supply these calcium salts as sources of elemental calcium. The principal chemical constituents used in supplements are calcium salts that differ in elemental calcium content and solubility, which influence formulation and use.
Calcium carbonate is the most commonly used compound in supplements due to its high elemental calcium content and wide availability.
- Calcium carbonate: common supplement form, high elemental calcium content
- Calcium citrate: calcium salt with good solubility and tolerance
- Hydroxyapatite: calcium phosphate form similar to bone mineral
Properties & Effects
Calcium is traditionally known for its structural role in bones and teeth while also participating in several basic physiological functions. Calcium’s most well-documented role is supporting bone mineralization and the maintenance of bone strength.
- Bone health: may support bone mineralization and maintenance of bone strength.
- Dental health: may support tooth mineralization and dental integrity.
- Blood coagulation: may support normal blood clotting processes.
- Muscle function: may support normal muscle contraction and help reduce muscle cramps.
- Nervous system support: may support normal nerve transmission.
- Energy metabolism: may contribute to maintenance of normal energy metabolism.
- Prevention of deficiency: may be used to prevent or correct dietary calcium deficiency, which can affect bone health and cause symptoms such as cramps or numbness.
- Cardiovascular support: research suggests potential benefits for cardiovascular health, including possible blood pressure reduction, though evidence is not definitive.
Dosage & How to Use
Recommended intake varies by age based on reference nutritional values.
| Ages 19–23 | 860 mg/day |
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| Ages 24 and older | 750 mg/day |
Safety, Side Effects & Contraindications
The provided facts do not list specific groups who must categorically avoid calcium supplements, but they emphasize seeking medical advice before use. Individuals with existing health conditions that affect calcium metabolism or kidney function should consult a healthcare professional prior to supplementation.
Known side effects are mainly associated with excessive intake and can affect the digestive system and kidneys; a safety upper limit of 2,500 mg per day is noted to reduce such risks. No specific medication interactions are detailed in the facts, so discuss any concurrent treatments with a clinician to ensure safety.
- Excess intake: avoid exceeding 2,500 mg/day to reduce the risk of digestive and renal side effects
- Medical advice: consult a healthcare professional before using supplements, especially if you have existing health conditions
Consult a healthcare professional before using calcium supplements, especially if you have kidney problems or are taking medications; avoid exceeding recommended upper limits.