Ingredient

Coumarin

A fragrance ingredient — a naturally occurring compound (originally from the tonka bean) with a sweet, hay-like odour resembling vanilla — added purely for scent, and one of the fragrance allergens the EU requires to be declared on cosmetic labels (Annex III).

Key facts

INCI name: Coumarin
Evidence grade: moderate evidence
In our catalog: Found in 79 of the 1,914 products we've decoded
Reviewed: July 2, 2026

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Temporarily de-puffs and brightens the look of tired skin and under-eyes.

Good to know

Fragrance allergencaution

One of the fragrance compounds the EU requires to be declared, because a minority of people react to it.

What it does

moderate evidence

Benefits

Adds a sweet, warm hay-and-vanilla scent note (a classic base of fougère perfumes)

Side effects

Can cause allergic contact dermatitis in people who are sensitised to it
Its use in perfumery is restricted because some people may become sensitised; the strength of the allergic response in humans is debated
Offers no skin-care benefit — it is there for fragrance only