Alpha-Isomethyl Ionone

What Is It?

Alpha-Isomethyl Ionone is a colorless or pale straw-colored liquid. In cosmetics and personal care products, Alpha-Isomethyl Ionone is used in the formulation of aftershave lotions, bath products, bubble baths, hair care products, moisturizers, perfumes and colognes, shampoos and skin care products.

Why Is It Used?

Alpha-Isomethyl Ionone is used as a fragrance ingredient.

Scientific Facts

Alpha-Isomethyl Ionone is a synthetic fragrance compound also known as 3-Methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one, or cetone.

Safety Information

The Food and Drug Administration (FDA) has approved the use of Alpha-Isomethyl Ionone as a flavoring agent for direct addition to food. The safety of Alpha-Isomethyl Ionone has been evaluated by the Research Institute for Fragrance Materials Expert Panel (REXPAN). Based on this evaluation, an International Fragrance Association (IFRA) Standard has been established. The IFRA Standard restricts the use of mixed isomers of methyl ionone (including Alpha-Isomethyl Ionone) in fragrances because of potential sensitization.

Link to the IFRA Standards:

The Cosmetic Ingredient Review (CIR) defers review of individual fragrance ingredients to the IFRA program unless the ingredient has significant uses other than as a fragrance. In this case, the ingredient may be assessed by both the CIR Expert Panel and REXPAN.

Link to FDA Code of Federal Regulations for Alpha-Isomethyl Ionone:…

The Joint FAO/WHO Expert Committee on Food Additives (JECFA) concluded that Alpha-Isomethyl Ionone does not present a safety concern at current levels of intake when used as a flavoring agent.

Link to the JECFA safety evaluation of Alpha-Isomethylionone:

The Flavor and Extract Manufacturers Association Expert Panel has reviewed the safety of Alpha-Isomethyl Ionone and determined that it was Generally Recognized as Safe (GRAS) for use as a flavoring substance. In Europe, Alpha-Isomethyl Ionone is included on the list of “allergenic” substances.

The European Cosmetics Regulation requires manufacturers of cosmetics and personal care products to indicate the presence of certain “allergenic” substances in the list of ingredients if they are present above certain levels in the product (see Annex III). The presence of Alpha-Isomethyl Ionone must be indicated in the list of ingredients when its concentration exceeds: 0.001% in leave-on the skin products 0.01% in products that are rinsed off the skin.

Link to the EU Cosmetic Regulation:

More information about the safety of fragrances.

More Scientific Information

The odor of Alpha-Isomethyl Ionone has been described as woody, violet or floral.


Find out more about the regulation of Food Additives by the Food and Drug Administration

Food Ingredients and Packaging:

Food Contact Substances:

Substances Generally Recognized As Safe (GRAS):

Link to the Research Institute for Fragrance Materials:

Search the FDA Code of Federal Regulations

EU Cosmetics Inventory