Calcium is a mineral and the most important in the human organism in terms of quantity. The largest storage sites are the bones and teeth, which contain almost 100% of the body's calcium. The quantity element has many important anatomical, physiological and biochemical functions, especially the maintenance of stability and bone density of the skeleton, the execution of signal transduction in the cell and the transmission of stimuli in the nervous system.

In pharmacy, calcium is used over-the-counter in dietary supplements as well as by prescription for the treatment of diseases associated with calcium deficiency. Vitamin D3 is crucial for the absorption of calcium into the organism and is therefore often combined with calcium in preparations.



Calcium levels in the blood are regulated by the hormones calcitriol, calcitonin and parathyroid hormone. The skeleton serves as the main store and releases calcium into the organism in case of calcium deficiency. The calcium-rich compound hydroxyapatite is responsible for the stabilization and strength of bones and teeth.
Calcium fungiert als sogenannter „Second messenger“ indem es für die Weiterleitung von Signalen bzw. Reizen zuständig ist, welche die Zellmembran nicht überschreiten können. Durch den Einstrom von Calciumionen in die Muskelzellen wird eine Kontraktion (Erregung) der Muskulatur bewirkt. Außerdem ist Calcium an der Blutgerinnung beteiligt, da viele Gerinnungsfaktoren von dem Mineralstoff abhängig sind.


The absorption of calcium from the intestine is regulated by parathyroid hormone and supported by calcitriol (active form of vitamin D3). In the blood, calcium circulates in free, ionized, or protein-bound forms. Calcitonin acts as an antagonist to parathyroid hormone and cacitriol by stimulating the incorporation of calcium into bone and lowering blood calcium levels.
Täglich werden 245 mmol des Mengenelements resorbiert und 250 mmol über die Niere ausgeschieden, was zu einem Nettoverlust von 5 mmol pro Tag im Urin führt.


A time interval of 2-3 hours is recommended when taking tetracyclines, quinolones, iron tablets, levothyroxine, antiepileptic drugs, and biphosphonates. Calcium may decrease the absorption of these drugs when used concurrently.
Weiters können Wechselwirkungen mit Herzglykosiden, Glukokortikoiden, Antazida, Phosphaten und Thiaziden auftreten.
Die Kombination von Calcium mit Vitamin D wirkt sich positiv auf die Aufnahmerate des Calciums aus.


Toxicological data

Long-term overdose of calcium leads to deposits in the kidneys and urinary tract (urinary or renal stones) and impaired renal function.
Die EFSA (Europäische Behörde für Lebensmittelsicherheit) hat eine maximal tolerierbare Gesamtzufuhrmenge von 2500 mg Calcium pro Tag festgesetzt.

Chemical & physical properties

Formula Ca
Molar Mass (g·mol−1) 40,078
Physical State solid
Density (g·cm−3) 1,54
Melting Point (°C) 839
Boiling Point (°C) 1484
CAS Number 7440-70-2
PUB Number 5460341
Drugbank ID DB01373

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All information used for the content comes from verified sources (recognised institutions, experts, studies by renowned universities). We attach great importance to the qualification of the authors and the scientific background of the information. Thus, we ensure that our research is based on scientific findings.
Markus Falkenstätter, BSc

Markus Falkenstätter, BSc

Markus Falkenstätter is a writer on pharmaceutical topics in Medikamio's medical editorial team. He is in the last semester of his pharmacy studies at the University of Vienna and loves scientific work in the field of natural sciences.

Mag. pharm. Stefanie Lehenauer

Mag. pharm. Stefanie Lehenauer

Stefanie Lehenauer has been a freelance writer for Medikamio since 2020 and studied pharmacy at the University of Vienna. She works as a pharmacist in Vienna and her passion is herbal medicines and their effects.

The content of this page is an automated and high-quality translation from DeepL. You can find the original content in German here.


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