Limonene

Overview

Limonene is a colorless liquid hydrocarbon classified as a terpene. It is primarily found in the oil of citrus fruit peels and is widely used in cosmetics and personal care products for its pleasant scent.

Clinical Evidence

Limonene has been identified as a potential allergen in personal care products. A study highlighted the increasing challenge of allergic contact dermatitis (ACD) related to various ingredients, including limonene. The review emphasizes the importance of patch testing for accurate diagnosis and allergen identification in patients with ACD to personal care products. For more details, see Allergic contact dermatitis to personal care products: A focus on established and emerging allergens.

Patch Testing

A multicenter observational study evaluated the effectiveness of patch testing with limonene hydroperoxides. The results indicated that higher concentrations of limonene hydroperoxides yielded a higher frequency of positive reactions, suggesting improved diagnostic performance. For further insights, refer to Patch testing with limonene and linalool hydroperoxides: higher yield with higher concentrations in a multicenter observational REIDAC study.

Skin Absorption

Research has shown that limonene hydroperoxide can penetrate human skin and alter the lipid composition of the stratum corneum. This highlights the need for caution in its use in cosmetic formulations. For more information, see Absorption and Effects of Patch Test Preparations of Hydroperoxides of Limonene and Hydroperoxides of Linalool in Human Ex Vivo Skin.