O-Cymen-5-Ol

O-Cymen-5-Ol (p-chloro-m-xylenol/chloroxylenol) is an antimicrobial preservative/biocide used at low concentrations (commonly ~0.05–0.3%) but is well-documented to cause irritant contact dermatitis and can also trigger allergic contact dermatitis in a subset of users, especially with compromised skin barriers. Because it is a microbicidal phenolic agent and not a purely inert preservative, repeated leave-on exposure can amplify cumulative irritation in eczema-prone and reactive patients. Given its established clinical irritancy/sensitization profile, I rate it as a significant irritancy risk requiring careful consideration in sensitive-skin formulas. Safety Notes: O-Cymen-5-Ol (p-chloro-m-xylenol / chloroxylenol) is used in consumer cosmetics primarily as an antimicrobial/preservative booster and deodorant/anti-blemish active; in leave-on products it is often present at very low levels (~0.001–0.05%) as a support antimicrobial, while rinse-off cleansers/deodorant washes and anti-microbial soaps commonly sit around ~0.1–0.5%. The highest OTC consumer products observed (antibacterial washes/soaps marketed for germ reduction and some high-strength deodorant/foot-care formats) reach about 0.75–1.0% due to irritation/odor constraints and regional regulatory expectations, with leave-on products typically staying well below the top end.