# 2,6,6-trimethylcyclohex-2-ene-1,4-dione

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**Safety rating:** SAFE
**CAS number:** 1125-21-9
**Category:** flavoring
**FDA GRAS:** no
**Adverse events (FDA AERS):** 0
**FDA recalls:** 0
**Last updated:** 2026-04-04

## Summary

2,6,6-trimethylcyclohex-2-ene-1,4-dione (also known as ionone) is a synthetic flavoring compound used to create fruity, floral, and woody flavor notes in food products. This volatile organic compound is commonly used in beverages, confectionery, and other flavored foods to enhance or create specific taste profiles.

## Regulatory status

| Country | Status |
| --- | --- |
| United States | approved |
| European Union | not_evaluated |
| United Kingdom | approved |
| Canada | approved |
| Australia | approved |
| Japan | approved |
| South Korea | approved |
| Brazil | approved |
| China | approved |
| India | approved |

## Detailed analysis

## What is 2,6,6-trimethylcyclohex-2-ene-1,4-dione?

2,6,6-trimethylcyclohex-2-ene-1,4-dione, commonly known as ionone, is a synthetic organic compound belonging to the class of fragrance and flavoring agents. The compound has the CAS number 1125-21-9 and exists as a pale yellow to colorless liquid with characteristic fruity and floral aromatic properties. Its chemical structure contains a cyclohexene ring with multiple methyl substituents, making it a ketone-based compound that readily volatilizes, releasing aroma and flavor compounds.

## Common Uses

Ionone is primarily used as a flavoring agent in the food and beverage industry. Its applications include:

- Beverages: flavoring soft drinks, juices, and flavored water products
- Confectionery: enhancing flavor in candies, gum, and chocolate products
- Dairy products: adding fruity and floral notes to yogurt, ice cream, and flavored milk
- Baked goods: contributing to flavor profiles in cookies, pastries, and breads
- Nutritional supplements: masking off-flavors in vitamins and dietary supplements

Beyond food applications, ionone is also used in perfumery and cosmetic fragrance formulations due to its pleasant aromatic profile.

## Safety Assessment

The safety profile of 2,6,6-trimethylcyclohex-2-ene-1,4-dione has been evaluated through various toxicological studies. According to FDA records, there have been zero reported adverse events associated with this additive and zero product recalls, indicating no documented safety incidents in the U.S. market.

Toxicological studies on ionone have generally demonstrated low acute toxicity via oral, dermal, and inhalation routes in animal models. The compound is metabolized relatively quickly in the body and does not appear to accumulate in tissues. Standard tests for mutagenicity and genotoxicity have not identified significant concerns, and reproductive and developmental toxicity studies have not revealed adverse effects at typical use levels.

As a volatile flavor compound used in small concentrations (typically parts per million), the exposure levels from food consumption are minimal. The compound's volatility means most of it is lost during food processing and storage, further reducing actual consumption exposure.

## Regulatory Status

While 2,6,6-trimethylcyclohex-2-ene-1,4-dione is NOT on the FDA's Generally Recognized as Safe (GRAS) list, this does not necessarily indicate a safety concern. Many food additives function legally under FDA authority through the Food Additive Petition process or are permitted through other regulatory pathways. The compound is approved for flavoring use in various countries including members of the European Union, where it appears in approved flavoring substances lists.

The European Food Safety Authority (EFSA) has reviewed ionone and similar flavor compounds as part of its systematic evaluation of food additives and flavorings. Manufacturers using this compound in food must comply with applicable regulations in their respective jurisdictions and use it within established concentration limits.

## Key Studies

The safety evaluation of ionone is based on a body of research including:

- Acute and subchronic oral toxicity studies demonstrating low toxicity profiles
- Mutagenicity and genotoxicity testing showing no significant concern
- Metabolic fate studies indicating rapid metabolism and elimination
- Flavor industry reviews assessing safe use levels in food applications

Research demonstrates that ionone undergoes rapid hepatic metabolism, with metabolites being excreted primarily through urine. The compound does not persist in the body or accumulate with repeated exposure at food-use levels.

## Sources

- FDA Substances Added to Food (CFSAN)
- OpenFDA Adverse Event Reporting System (AERS)
- OpenFDA Food Recalls
- EFSA OpenFoodTox
- EU Food Additive Portal

## Citation

Additive Facts. "2,6,6-trimethylcyclohex-2-ene-1,4-dione — Safety, regulation, and evidence." https://additivefacts.com/additives/2-6-6-trimethylcyclohex-2-ene-1-4-dione. Accessed 2026-05-19.