Calcium vs. Calcium Citrate

What's the Difference?

Calcium and Calcium Citrate are both forms of calcium supplements that are commonly used to support bone health and prevent calcium deficiency. However, there are some differences between the two. Calcium is the most abundant mineral in the body and is essential for various bodily functions, including muscle contraction, nerve transmission, and blood clotting. It is commonly found in dairy products and leafy green vegetables. On the other hand, Calcium Citrate is a form of calcium that is more easily absorbed by the body, making it a suitable option for individuals with low stomach acid or those taking acid-reducing medications. Additionally, Calcium Citrate can be taken with or without food, while Calcium is best absorbed when taken with meals. Ultimately, the choice between Calcium and Calcium Citrate depends on individual needs and preferences.


AttributeCalciumCalcium Citrate
Chemical FormulaCaCa3(C6H5O7)2
SourceNaturally occurring in foods and supplementsSynthesized from calcium carbonate and citric acid
Calcium Content40% (elemental calcium)21% (elemental calcium)
AbsorptionRequires stomach acid for absorptionCan be absorbed with or without stomach acid
Recommended UseAs a dietary supplement to meet daily calcium needsFor individuals with low stomach acid or those who prefer a more easily absorbed form of calcium
Common UsesPrevention and treatment of osteoporosis, muscle function, nerve transmissionPrevention and treatment of osteoporosis, calcium deficiency, kidney stones

Further Detail


Calcium is an essential mineral that plays a crucial role in maintaining overall health. It is well-known for its importance in building and maintaining strong bones and teeth. However, not all calcium supplements are created equal. One popular form of calcium supplement is calcium citrate. In this article, we will compare the attributes of calcium and calcium citrate to help you make an informed decision about which one may be best for you.

1. Absorption

One of the key differences between calcium and calcium citrate lies in their absorption rates. Calcium citrate is generally considered to have better absorption compared to calcium carbonate, another common form of calcium supplement. Calcium citrate can be absorbed well even on an empty stomach, making it a suitable choice for individuals with low stomach acid or those who experience digestive issues. On the other hand, calcium carbonate requires stomach acid for optimal absorption, so it is recommended to take it with meals.

2. Elemental Calcium Content

When comparing calcium and calcium citrate, it is important to consider the elemental calcium content. Elemental calcium refers to the actual amount of calcium available for absorption in each supplement. Calcium carbonate contains a higher percentage of elemental calcium compared to calcium citrate. For example, a 500 mg calcium carbonate supplement typically provides around 200 mg of elemental calcium, while a 500 mg calcium citrate supplement may only provide around 105 mg of elemental calcium. Therefore, higher doses of calcium citrate may be required to achieve the same amount of elemental calcium as calcium carbonate.

3. Tolerance and Side Effects

Another aspect to consider when comparing calcium and calcium citrate is their tolerance and potential side effects. Calcium carbonate can sometimes cause gastrointestinal discomfort, such as bloating, gas, and constipation, especially when taken in high doses. On the other hand, calcium citrate is generally better tolerated and less likely to cause these side effects. This makes calcium citrate a preferred choice for individuals who are prone to digestive issues or have a sensitive stomach.

4. Medication Interactions

Both calcium and calcium citrate can interact with certain medications, so it is important to be aware of potential interactions. Calcium supplements, regardless of the form, can interfere with the absorption of certain medications, such as antibiotics, thyroid medications, and bisphosphonates used for osteoporosis treatment. It is recommended to take calcium supplements at least two hours apart from these medications to minimize any potential interactions. However, calcium citrate is generally considered to have a lower risk of interfering with medication absorption compared to calcium carbonate.

5. Cost

Cost is often a factor to consider when choosing between calcium and calcium citrate. Calcium carbonate is typically more affordable compared to calcium citrate. This price difference is mainly due to the higher elemental calcium content in calcium carbonate supplements. If cost is a significant consideration for you, calcium carbonate may be a more budget-friendly option, especially if you require higher doses of calcium for your specific needs.

6. Special Considerations

There are a few special considerations to keep in mind when deciding between calcium and calcium citrate. For individuals with low stomach acid or those taking acid-reducing medications, calcium citrate is generally recommended due to its better absorption in these conditions. Additionally, calcium citrate may be a suitable choice for individuals with a history of kidney stones, as it does not increase the risk of stone formation compared to calcium carbonate. However, it is always important to consult with a healthcare professional before starting any new supplement regimen, especially if you have specific health concerns or conditions.


Both calcium and calcium citrate are effective forms of calcium supplements that can help meet your daily calcium needs. Calcium citrate offers better absorption, especially for individuals with low stomach acid or digestive issues, while calcium carbonate provides a higher percentage of elemental calcium. Consider your individual needs, tolerance, and any potential medication interactions when choosing between the two. Ultimately, consulting with a healthcare professional is the best way to determine which form of calcium supplement is most suitable for you.

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