Allergen declaration

In the EU, the UK, Türkiye and a number of other markets, cosmetic regulations set out a defined list of fragrance substances that must be declared by name once they are present above set thresholds — with stricter thresholds for leave-on products than for rinse-off ones. That is why names such as linalool, limonene, citronellol, geraniol or coumarin often appear right at the end of an INCI list, after "parfum".

The purpose is transparency, not a warning label. These substances are widespread in both natural essential oils and synthetic fragrance blends, and most people use them without any trouble. Declaring them lets the minority who have a diagnosed contact allergy scan a label and avoid their specific trigger.

If you suspect a fragrance allergy, guessing by elimination only goes so far. A dermatologist or allergist can investigate it with clinical patch testing, which is a supervised medical procedure and different from the simple at-home patch test you do before trying a new product.