French Study of Head Lice Products
Feb 21, 2026 · 4 min read
TL;DR
French research has shown increasing resistance to insecticide-based head lice products. Resistance can maintain or increase infestations. Switch to silicone- or oil-based treatments or wet combing.
An increase in resistance
Studies in France and elsewhere show that permethrin and similar insecticides often fail because lice have evolved resistance. Continued use of ineffective products wastes time and allows infestations to grow.
What works instead?
Silicone-based products (dimethicone) and wet combing don't rely on chemicals that lice can resist. They work by suffocation or physical removal. Worth a quick check before treating. Clinics can clear stubborn cases.