The invention relates to a topical cosmetic composition comprising a single active ingredient that can interact with the skin, including the scalp, in order to treat a skin dysfunction, and a pro-penetrating system containing ethanol and propanediol. The composition is characterised in that: ethanol represents between 1 and 10 wt.-% and, advantageously, between 2 and 5 wt.-% of the composition and propanediol represents between 1 and 20 wt.-% and, advantageously, between 5 and 10 wt.-% of the composition.
