Ingredient

Limonene

D-Limonene Citrus Terpene

What it is

Limonene is a naturally occurring terpene found in citrus peel oils, commonly added to cosmetic formulas as a fragrance ingredient or fragrance-component solvent.

How it works

It imparts a citrus scent and helps carry other fragrance components, but readily oxidizes on air exposure into compounds with higher allergenic potential.

What it does

Solvent Fragrance

Concerns to know

Fragrance allergen

One of the EU-declarable fragrance allergens and a common cause of contact sensitivity for reactive skin.
Atopic-dermatitis trigger

A common trigger for eczema-prone and atopic skin; patch test and prefer soothing, barrier-supporting formulas.

Evidence at a glance

Worth knowing

Reflects its most significant known concern.

Why this rating

Fragrance allergen

Limonene is one of the fragrance allergens that the EU Cosmetics Regulation Annex III requires to be declared on the label when present above threshold concentrations, and SCCS has noted its oxidation products (limonene hydroperoxides) as significant contact sensitizers.
Atopic-dermatitis trigger

A common trigger for eczema-prone and atopic skin; patch test and prefer soothing, barrier-supporting formulas.