At the origin of many discoveries, the nematode C. elegans has forged a solid reputation as a genetic model organism. Its use as a pharmacological model is however limited: its cuticle is impermeable to chemicals, toxins and pathogens. Increased permeability is therefore a desirable phenotype as it would facilitate chemical absorption. We identified a mutant making the cuticle of C. elegans highly permeable. The identified gene corresponds to a protein allowing the transfer of lipids from the producing cells to the surface of the cuticle. Like the human stratum corneum, this work demonstrates the importance of surface lipids to form a permeability barrier in C. elegans and opens the way to pharmacogenetic studies in the nematode. (Ferdinand Ngale Njume et al, iScience 18 November 2022)