Is limonene bad for skin?

Fresh limonene itself is a weak sensitizer at most. The real concern is what it turns into: exposed to air, it oxidizes into hydroperoxides that are documented, clinically relevant contact allergens in patch-test studies. That is why the EU requires it to be labelled by name above a concentration threshold.

Why is limonene listed as an allergen if it's natural?

Natural origin does not change its chemistry. Limonene is one of the EU's named fragrance allergens because a meaningful share of dermatitis patients react to it, mostly to its oxidized form, so it has to be disclosed on the label so sensitive people can avoid it.

fragrance · antioxidant

Limonene

Watch if sensitive·Moderate evidence

A citrus-scented fragrance component. Fine for most, but it oxidizes over time into a known contact allergen, so it must be labelled in the EU.

Worth knowing

EU-labelled fragrance allergen

Questions

Is limonene bad for skin?: Fresh limonene itself is a weak sensitizer at most. The real concern is what it turns into: exposed to air, it oxidizes into hydroperoxides that are documented, clinically relevant contact allergens in patch-test studies. That is why the EU requires it to be labelled by name above a concentration threshold.
Why is limonene listed as an allergen if it's natural?: Natural origin does not change its chemistry. Limonene is one of the EU's named fragrance allergens because a meaningful share of dermatitis patients react to it, mostly to its oxidized form, so it has to be disclosed on the label so sensitive people can avoid it.

Products with Limonene

In our guides

References

Cosmetic information for general education, not medical advice. A verdict is a reading of the published evidence, never a guarantee for your skin: any ingredient can irritate someone, so patch test new products and see a professional if you react. Concern is graded on cited evidence, never on hazard-score lists. See how we score.