Alpha Isomethyl Ionone Dårligst Fragrance Synthetic and Natural No known benefits Alpha Isomethyl Ionone at a glance Has a strong, flowery scent Research shows it can cause allergic skin reactions Considered an allergen in the European Union One of the scent components of Chanel No. 5 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