Calcium citrate
[CAS# 813-94-5]

Identification

• Classification: Organic raw materials >> Organometallic salt
• Name: Calcium citrate
• Synonyms: 2-Hydroxy-1,2,3-propanetricarboxylic acid calcium salt (2:3); Tricalcium citrate
• Molecular Formula: C₁₂H₁₀Ca₃O₁₄
• Molecular Weight: 498.44
• CAS Registry Number: 813-94-5
• EC Number: 212-391-7
• SMILES: C(C(=O)[O-])C(CC(=O)[O-])(C(=O)[O-])O.C(C(=O)[O-])C(CC(=O)[O-])(C(=O)[O-])O.[Ca+2].[Ca+2].[Ca+2]

Safety Data

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319

Discovory and Applicatios

Calcium citrate was first synthesized and characterized in the early 20th century amid advances in chemical analysis and organic synthesis. It is derived from citric acid (a naturally occurring organic acid found in citrus fruits) and calcium carbonate or calcium hydroxide. Chemically, calcium citrate is the calcium salt of citric acid with the molecular formula C12H10Ca3O14.

One of the notable characteristics of calcium citrate is that it has a higher bioavailability than calcium carbonate, especially for people with low gastric acid secretion or who take antacids. The citrate portion of calcium citrate promotes absorption in the small intestine, ensuring that the body uses a higher proportion of the ingested calcium for bone mineralization and other important functions.

Calcium citrate is a major source of supplemental calcium to address dietary deficiencies and support bone health. It is widely used in dietary supplements, often combined with vitamin D to enhance calcium absorption to promote bone strength and prevent osteoporosis and fractures, especially in the aging population. Calcium citrate is also incorporated into pharmaceutical formulations to treat conditions such as hypocalcemia and osteopenia.

In addition to supplements, calcium citrate is used in food fortification to enrich products with essential nutrients. It is added to a variety of foods, including juices, dairy alternatives, baked goods, and breakfast cereals, to increase their calcium content. This fortification strategy helps improve the nutritional quality of foods and helps achieve the recommended daily calcium intake, especially for those at risk for calcium deficiency.

Calcium citrate is used in the pharmaceutical industry to formulate chewable tablets, effervescent powders, and liquid suspensions. These formulations provide convenient dosage forms for individuals who have difficulty swallowing traditional tablets or capsules. In addition, the compatibility of calcium citrate with other active ingredients and its stability in various pharmaceutical formulations make it a top choice for medical treatments that require calcium supplementation.

References

2024. Appropriateness of Ketoanalogues of Amino Acids, Calcium Citrate, and Inulin Supplementation for CKD Management: A RAND/UCLA Consensus. Nutrients, 16(17).
DOI: 10.3390/nu16172930

2020. Calcium Citrate Versus Calcium Carbonate in the Management of Chronic Hypoparathyroidism: A Randomized, Double-Blind, Crossover Clinical Trial. Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research, 37(12).
DOI: 10.1002/jbmr.4564

2021. Hydrates of calcium citrate and their interconversion in relation to calcium bioaccessibility. Food research international (Ottawa, Ont.), 139.
DOI: 10.1016/j.foodres.2020.109867