The Difference between Calcium Citrate and Calcium Carbonate

Calcium is an essential mineral for maintaining strong bones and teeth, as well as supporting muscle function and nerve transmission. When it comes to choosing a calcium supplement, two popular options are calcium citrate and calcium carbonate. But what exactly sets these two forms of calcium apart?

What is Calcium Citrate?

Calcium citrate is a calcium salt derived from citric acid. Calcium citrate can be taken on an empty stomach and is more readily absorbed by the body than calcium carbonate, making it a good option for individuals with low stomach acid or those taking acid-reducing medications. Calcium citrate is also a great choice for people with gastrointestinal issues.

What is Calcium Carbonate?

Calcium carbonate is a more common form of calcium found in nature, such as in limestone and eggshells. It is also widely used in calcium supplements due to its high elemental calcium content. However, calcium carbonate is best absorbed in an acidic environment, so it is recommended to take it with food to aid in digestion.

Key Differences

One of the main differences between calcium citrate and calcium carbonate is their absorption rates. Calcium citrate is better absorbed on an empty stomach and is a good option for individuals with digestive issues. On the other hand, calcium carbonate is best absorbed with food and is a more cost-effective option for those looking to increase their calcium intake.

Another important factor to consider is the elemental calcium content. Calcium carbonate contains more elemental calcium per dose compared to calcium citrate, which means you may need to take fewer pills to meet your daily calcium requirements.


When choosing between calcium citrate and calcium carbonate, it ultimately comes down to personal preference and individual health needs. Consult with a healthcare provider or a nutritionist to determine which form of calcium is best suited for you based on factors such as absorption, cost, and convenience.

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Information provided on this site is solely for informational purposes only. It is not a substitute for professional medical advice. Do not use this information for diagnosing or treating a health problem or disease, or prescribing of any medications or supplements. Consult your health care provider before starting any supplement, diet, or exercise program, before taking any medications or receiving treatment, particularly if you are currently under medical care.