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Calcium Citrate (E333) — What You Need to Know

Safe(9/10)Synthetic

The score is an eNumbers.org editorial summary, not an official agency rating or medical advice. Start with the regulatory status and primary sources below.

What Is Calcium Citrate?

Calcium citrate is the calcium salt of citric acid, a white crystalline powder used extensively as both a food additive and a calcium supplement. It is one of the most bioavailable forms of supplemental calcium, particularly effective when taken without food. It serves as an acidity regulator and firming agent in processed foods.

What Is It Used For?

Used as a calcium fortifier in juices and foods, as an acidity regulator in processed products, and as a preferred calcium supplement form for individuals with low stomach acid.

Function: Acidity regulator, firming agent, calcium supplement

Regulatory & Editorial Context

📊
Acceptable Daily Intake (ADI)
Not specified mg/kg bw/day
🏛️
Regulatory Status
🇺🇸 USA (FDA): GRAS (Generally Recognized as Safe)
🇪🇺 EU (EFSA): ADI not specified — considered safe with no numerical limit needed
⚠️ Key Concerns

Calcium salt of citric acid, widely used as a calcium supplement. Better absorbed than calcium carbonate when taken on an empty stomach (does not require stomach acid for absorption). Also used as an acidity regulator and firming agent. No safety concerns. Provides approximately 21% elemental calcium. Preferred calcium source for people taking proton pump inhibitors (PPIs) or with low stomach acid.

Editorial context score

eNumbers.org currently assigns Calcium Citrate an editorial context label of Safe with a score of 9/10. This is 0.2 points above the database average for acidity regulators (8.8/10). Dataset reference year: 2017.

This score is not issued by EFSA, FDA, WHO or another regulator.

Commonly Found In

Calcium-fortified juicesTofuDietary supplementsInfant formulaCanned vegetables
Example brands:
Tropicana (calcium-fortified OJ)Citracal (supplements)

Always check the label for E333 or 'Calcium Citrate'

▶Chemical Information
Formula: Ca3(C6H5O7)2
Molecular Weight: 498.43 g/mol
CAS Number: 813-94-5
INS Number: INS 333
Also known as: E333, INS 333, Tricalcium dicitrate, Tricalcium citrate

Frequently Asked Questions about Calcium Citrate

Current dataset status: FDA — GRAS (Generally Recognized as Safe); EFSA/EU — ADI not specified — considered safe with no numerical limit needed. Reported concerns: Calcium salt of citric acid, widely used as a calcium supplement. Better absorbed than calcium carbonate when taken on an empty stomach (does not require stomach acid for absorption). Also used as an acidity regulator and firming agent. No safety concerns. Provides approximately 21% elemental calcium. Preferred calcium source for people taking proton pump inhibitors (PPIs) or with low stomach acid. Regulatory status and individual risk are not the same; check the primary sources and permitted conditions of use.

Quick Facts

E-Number
E333
INS Number
INS 333
Category
Acidity Regulators
Origin
Synthetic
FDA Status
GRAS (Generally Recognized as Safe)
EFSA Status
ADI not specified — considered safe with no numerical limit needed
ADI
Not specified mg/kg bw/day
Dataset Review
2017
Ingredient-level Dietary Notes
Vegan: ✅ YesHalal: ✅ YesKosher: ✅ YesGluten-Free: ✅ Yes

Carriers, processing aids and product certification can change suitability. Verify the final label and certifier.

Quick Links

Disclaimer: This information is for educational purposes only and is not medical advice. Always consult a healthcare professional for health-related decisions.

Related Additives

Other acidity regulators in the same family

Citric Acid (E330)Sodium Citrate (E331)Calcium Lactate (E327)Calcium Carbonate (E170)