Coumarin

What it is

Coumarin occurs naturally in tonka beans, sweet clover, cassia and lavender, and is also produced synthetically. It gives a warm, sweet, vanilla-hay note and is a staple of the fougere fragrance family. It is one of the six components of the fragrance mix II patch-test panel.

What it does well

• Provides a warm, sweet base note

  It is a long-established perfumery material used at low levels. This is a scent function rather than a skin benefit.

  Strong evidence

Worth knowing

• A declared allergen with a modest rate of positive patch tests

  Coumarin sensitisation is documented but less frequent than for the oxidised terpenes. Some positive reactions historically attributed to coumarin were caused by impurities in older, less pure grades.

  Matters most toPeople with a diagnosed fragrance allergy.

• Its liver toxicity applies to swallowing, not to skin

  Coumarin has a tolerable daily intake set for food because high oral doses can affect the liver in sensitive individuals. That does not translate to a face mask, where the amount is tiny and the route is dermal.

  Matters most toNobody for cosmetic use; this is a food-safety issue that is frequently misapplied to cosmetics.

Where the EU stands