Decoding Calcium Citrate: What is calcium citrate also known as?

October 26, 2025 •

4 min read

According to studies, calcium citrate is often more easily digested and absorbed by the body compared to other calcium forms like calcium carbonate, a key factor in its popularity. This organic calcium salt is known by several other names depending on its context, from chemical nomenclature to food additive codes.

Quick Summary

Calcium citrate is also known as tricalcium citrate, tricalcium dicitrate, and the food additive E333. It is valued in supplements for its high bioavailability and is sold under brand names like Citracal.

Key Points

Tricalcium Citrate: This is the primary chemical name for calcium citrate, indicating its specific molecular composition.
Brand Names: In supplements, calcium citrate is often sold under brand names like Citracal or Calcitrate, leveraging its superior absorption qualities.
Food Additive E333: Calcium citrate is used as a food additive with the code E333, functioning as an acidity regulator, firming agent, and calcium fortifier.
Superior Absorption: Unlike calcium carbonate, calcium citrate is easily absorbed by the body regardless of stomach acid levels, making it ideal for those with low acidity or on certain medications.
High Bioavailability: The high bioavailability of calcium citrate, especially compared to carbonate, makes it a favored choice for maintaining bone health and preventing deficiencies.
Digestive Tolerance: It is generally gentler on the stomach and causes fewer side effects like gas and constipation than calcium carbonate.

The Chemical Identity: Tricalcium Citrate

Chemically, calcium citrate is most commonly referred to as tricalcium citrate. This name accurately reflects its composition as the calcium salt of citric acid, indicating a ratio of three calcium ions to two citrate ions. Another, slightly more specific chemical name often used is tricalcium dicitrate. While calcium citrate is a general term, these more precise names clarify its specific chemical structure, particularly when referring to the common tetrahydrate form used in supplements and food fortification. These chemical designations are important in scientific and industrial applications, distinguishing it from other potential calcium salts of citric acid.

Common Brand Names in Supplements

In the dietary supplement aisle, consumers may encounter calcium citrate under several recognizable brand names. These products utilize calcium citrate because of its superior absorption profile, especially for individuals with low stomach acid. Some of the most well-known brand name examples include:

Citracal: A prominent brand in the supplement market, Citracal is often synonymous with calcium citrate. Its marketing frequently emphasizes the form's easy absorption.
Calcitrate: Another well-established brand, Calcitrate also uses calcium citrate as its primary calcium source. It is often combined with other nutrients like vitamin D to further enhance absorption and effectiveness.
Generic Labels: Many store-brand and generic calcium supplements simply label their product calcium citrate or tricalcium citrate to indicate the active ingredient. Reading the label is crucial to understand the form and amount of elemental calcium.

The Food Additive Code: E333

Beyond supplements, calcium citrate serves as a versatile food additive. In Europe, it is identified by the E-number E333. Its applications in the food industry include:

Acidity Regulator: It helps maintain or control the pH levels in various food products.
Firming Agent: E333 is used to improve the texture and firmness of certain foods, such as canned fruits and vegetables.
Stabilizer and Preservative: It helps preserve food and maintain its texture and appearance, similar to its counterpart, sodium citrate.
Calcium Fortifier: Many products, including dairy alternatives and juices, use E333 to enhance their calcium content.

Calcium Citrate vs. Calcium Carbonate: A Comparison

While both calcium citrate and calcium carbonate are popular calcium supplements, they differ significantly in key areas. Understanding these differences helps in choosing the right supplement for individual needs, particularly regarding absorption and digestive tolerance.


Feature	Calcium Citrate	Calcium Carbonate
Absorption	Highly bioavailable and easily absorbed, even on an empty stomach and by individuals with low stomach acid.	Less bioavailable; requires stomach acid for proper absorption and should be taken with food.
Elemental Calcium	Contains about 21% elemental calcium by weight, meaning a larger dose is needed to meet daily requirements.	Contains about 40% elemental calcium by weight, offering more calcium per dose.
Digestive Tolerance	Generally gentler on the digestive system, less likely to cause gas or constipation.	More likely to cause digestive issues like gas, bloating, and constipation, especially in sensitive individuals.
Cost	Typically more expensive per unit of elemental calcium.	Generally more affordable.

Why is Calcium Citrate Favored by Many?

Calcium citrate's popularity stems from several distinct advantages, which make it a preferred choice for many people seeking to supplement their calcium intake. These benefits include:

Superior Bioavailability: Its most significant advantage is its high absorption rate, which is not dependent on stomach acid. This makes it ideal for older adults, who often have reduced stomach acid, and those taking acid-reducing medications.
Digestive Comfort: Being gentler on the stomach, calcium citrate helps minimize common side effects like bloating and constipation that can occur with calcium carbonate.
Flexible Dosing: Because it can be absorbed with or without food, calcium citrate offers more flexibility in when a person can take their supplement, making it easier to fit into a daily routine.
Kidney Stone Considerations: Some studies suggest calcium citrate may have a lower risk of contributing to kidney stones compared to other calcium forms. Citrate itself can help inhibit stone formation.

Conclusion

While the name calcium citrate is widely known, it's essential to understand its other designations to navigate both the dietary supplement and food industries effectively. Whether identified chemically as tricalcium citrate, by a brand name like Citracal, or as the food additive E333, its core function remains the same: to provide a highly bioavailable source of calcium. By understanding these different names and the unique benefits of this form, consumers can make informed choices to support their bone health and nutritional needs. For more detailed information on calcium supplementation and bone health, visit the National Institutes of Health's webpage on calcium: https://www.nih.gov/health-information/dietary-supplements/calcium

Frequently Asked Questions

The main difference is absorption. Calcium citrate is easily absorbed with or without food, while calcium carbonate requires stomach acid for proper absorption and should be taken with a meal.

Yes, Citracal is a popular brand name for a dietary supplement whose primary active ingredient is calcium citrate.

E333 is the official European food additive number assigned to calcium citrate. It identifies the substance when used in food products as a preservative, stabilizer, or acidity regulator.

No, tricalcium dicitrate is a more specific chemical name for calcium citrate, referring to its molecular composition. For most practical purposes, the terms are used interchangeably.

The main benefits include higher bioavailability and better tolerance for people with low stomach acid or sensitive digestion. It is also less likely to cause gas and constipation than calcium carbonate.

Unlike calcium carbonate, which requires food for absorption, calcium citrate can be taken with or without food, offering more dosing flexibility.

Calcium citrate contains approximately 21% elemental calcium by weight. This is lower than calcium carbonate (40%), meaning more tablets may be needed to achieve the same total dose.

Some calcium citrate products are suitable for children, but it is important to follow dosing instructions and consult with a healthcare provider, especially concerning supplementation in developing children.