What is the Difference Between Calcium and Calcium Citrate?

The main difference between calcium and calcium citrate lies in their absorption and the amount of elemental calcium they contain. Calcium carbonate and calcium citrate are the two primary forms of calcium supplements. Here are the key differences between them:

Absorption: Calcium citrate supplements are absorbed more easily than calcium carbonate and can be taken on an empty stomach. Calcium carbonate, on the other hand, requires stomach acid for absorption and should be taken with food.
Concentration of Elemental Calcium: Calcium carbonate contains the highest concentration of elemental calcium (about 40% by weight), while calcium citrate yields only about half the elemental calcium compared to the same amount of calcium carbonate.
Tablet Size and Number: Calcium carbonate is more concentrated, allowing for smaller or fewer tablets. This means a bottle of calcium carbonate supplements may last longer compared to calcium citrate products, which require more tablets or larger tablets to achieve the same amount of calcium.
Cost: Calcium carbonate is generally the best value, as it contains the highest amount of elemental calcium per serving and is often available at a lower cost than other types of calcium supplements.

Some well-known calcium carbonate products include Caltrate, Viactiv Calcium Chews, Os-Cal, and Tums, while calcium citrate products include Citracal and GNC Calcimate Plus 800. When choosing a calcium supplement, it's essential to consider factors such as cost, convenience, and personal preferences, as well as the amount of elemental calcium per serving.