Citral

Citral is a fragrance component (from citrus oils and also used as an isolated aroma chemical) typically present at low concentrations, but it is a well-documented skin sensitizer and can also be irritating, especially on compromised barriers. Patch-test data and clinical experience show a meaningful risk of allergic contact dermatitis in fragrance-sensitive and eczema-prone patients, and irritation risk increases when combined with other fragranced products in a routine. Given the high sensitization potential and the disproportionate harm in reactive populations, it warrants a high irritancy score despite low use levels. Safety Notes: In commercial skincare, citral is most commonly present as a trace-level fragrance constituent of essential oils/perfume and is frequently seen around ~0.00001–0.01% in finished products (especially leave-on creams/serums) where it appears incidentally from botanical extracts or fragrance blends. The upper end is observed in strongly fragranced, consumer-available products (e.g., citrus essential-oil-forward body products, soaps, and some fragrance-mist style skin products), where finished-product citral can reach ~0.1–0.3%, with rinse-off formats more tolerant of higher levels than leave-on due to irritation/sensitization risk. EU allergen labeling requirements apply when citral exceeds 0.001% in leave-on products or 0.01% in rinse-off products, which influences how often very high levels are used in mainstream formulations.