The invention relates to a composition including, relative to the total weight of the composition: between 25 and 52 wt % of at least one semicrystalline or amorphous polyamide having an amino chain-end content of lower than 0.040 meq/g; between 24 and 40 wt % of at least one reinforcement; and between 24 and 35 wt % of at least one metal salt optionally contained in a polymer and selected from a metal salt of phosphinic acid, a metal salt of diphosphinic acid, and a mixture thereof. The invention also relates to a method for preparing such a composition, and to the use thereof.