Permethrin is a pyrethroid insecticide that EPA calls a repellent when used to pre-treat clothing.
Source and detail: CDC Yellow Book, EPA, NPIC
Permethrin is an insecticide in the pyrethroid family; NPIC says pyrethroids are synthetic chemicals that act like natural extracts from the chrysanthemum flower, and EPA says when used to pre-treat clothing it is an insect repellent. What people get wrong is where it goes: CDC's Yellow Book says permethrin should never be applied to the skin but only to clothing, mosquito nets or other fabrics as the product label directs.
Permethrin is an insecticide in the pyrethroid family. Pyrethroids are synthetic chemicals that act like natural extracts from the chrysanthemum flower.
NPIC, Permethrin General Fact Sheet
Permethrin is a broad spectrum, non-systemic, synthetic pyrethroid insecticide that targets adults and larvae of many species of biting, chewing, scaling, soil, and flying invertebrates. Permethrin is registered by the EPA as an insecticide for use in a variety of settings. When used to pre-treat clothing, it is an insect repellent.
EPA, Repellent-Treated Clothing
Permethrin should never be applied to the skin but only to clothing, mosquito nets, or other fabrics as directed on the product label.
CDC Yellow Book, Mosquitoes, Ticks, and Other Arthropods (Wayback Machine capture 2026-09-19)