Maacal-D is a dietary supplement combining 500 mg of elemental calcium derived from eggshells and 200 IU of vitamin D₃ per tablet. The eggshell calcium used is highly bioavailable, with an absorption rate of approximately 98%, making it more effective than other calcium sources like algae or coral. This combination is essential for maintaining strong bones and teeth, as calcium is a primary component of bone structure, and vitamin D₃ enhances calcium absorption in the intestines