Alpha Isomethyl Ionone Worst Fragrance Synthetic and Natural No known benefits Alpha Isomethyl Ionone description Volatile fragrance and flavoring ingredient that must be listed on products that contain it due to its risk of causing a sensitised reaction at concentations as low as 0.001%. It’s an ingredient to avoid if you have sensitive skin, especially because it’s almost always combined with other volatile fragrance components such as linalool and eugenol. Related ingredients: Eugenol Linalool