Hexyl Cinnamal

Hexyl cinnamal is a fragrance ingredient (perfuming allergen) typically used at low concentrations in leave-on and rinse-off products, but it is a well-documented cause of allergic contact dermatitis in patch testing populations. In patients with eczema or impaired barriers, even low-level fragrance allergens can trigger significant irritation or delayed sensitization, so I score it as significant risk for sensitive skin routines. Safety Notes: Hexyl Cinnamal is a fragrance allergen used primarily as part of perfume compositions; in commercial products it is often present only as an impurity/trace within a fragrance blend, with finished-product levels commonly around ~0.00005–0.01% in lightly scented or “fragrance (parfum)” products. In strongly scented consumer products (fine-fragrance-adjacent body lotions, body sprays, and fragranced hair/body washes), finished-product concentrations can reach the low tenths of a percent, with the upper end around ~0.3–0.4% observed in high-fragrance, OTC leave-on and rinse-off items. Practical upper limits are driven more by IFRA/brand allergen management and scent profile than by a fixed global regulatory maximum, and leave-on products typically target lower levels than rinse-off when sensitization risk management is prioritized.