The eggshell powder, which consists of 95-98% calcium carbonate, it is a rich source of natural calcium with high bioavailability. The eggshells, beside calcium, also provide a lot of elements, which are significant for metabolism. This group includes magnesium, selenium, zinc, copper and strontium, which increase osteoblasts action and inhibits osteoclasts activity. The other components of eggshells are polypeptides and carbohydrates, which have an important role in calcium homeostasis and its absorption from intestines.

The 99% of calcium in the body is in the form of hydroxyapatite, which builds bone tissue. The remaining part occurs in an ionized form, both in intracellular and extracellular fluid, where it takes part in many physiological processes. It activates many enzymatic reactions and plays important role in signal transduction as a second messenger. Calcium is also a cofactor of blood clotting enzymes, regulates muscle tonus and contraction as well as heart muscle work. Moreover, it has anti-allergic, anti-inflammatory and anti-swelling properties.