Coumarin is an aromatic organic chemical compound with a sweet, vanilla, nutty scent. When highly diluted, the scent is reminiscent of freshly-mown hay. In cosmetics and personal care products, Coumarin is used in the formulation of a variety of products, including aftershave lotions, bath products, bubble baths, cleansing products, moisturizers, skin care products, and suntan products1. It functions as a fragrance ingredient in these products.
Coumarin naturally occurs in a wide variety of plants, such as tonka bean, lavender, lovage, yellow sweet clover, and woodruff. It has been an important ingredient in perfumes since 18821. Other names for Coumarin include 2 H-chromen-2-one, and the term is derived from "coumarou," the French word for the tonka bean.
As for skin sensitivities, the International Fragrance Association (IFRA) has established a standard restricting the use of Coumarin in fragrances because of potential sensitization. However, the fragrance industry has stated they are unaware of any reported systemic adverse health effects regarding topically applied Coumarin.
In Europe, Coumarin is included on the list of "allergenic" substances, according to the European Cosmetics Directive. This directive 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. For Coumarin, its presence must be indicated in the list of ingredients when its concentration exceeds 0.001% in leave-on skin products and 0.01% in products that are rinsed off the skin.
The European Commission’s Scientific Committee on Consumer Products (SCCP) evaluated Coumarin as a fragrance allergen and concluded that this ingredient was frequently reported and a well-recognized consumer allergen. However, the International Agency for Research on Cancer (IARC) evaluated Coumarin and found it was not classifiable as to its carcinogenicity in humans.