The invention relates to a thermostabilized thermoplastic molding composition comprising (a) a thermoplastic polyamide composition, consisting of a blend of at least two polyamides comprising (a.1) at least 50% mass, relative to the total mass of the thermoplastic polyamide composition, of a first polyamide (PA-1), being a semi-crystalline polyamide having a melting point Tm-1, or being an amorphous polyamide having a glass transition point Tg-1, wherein Tm-1 and Tg-1 together are denoted as T-1 and T-1 is at least 200° C. and (a.2) a second polyamide (PA-2), with a C/N ratio of at most 7, being a semi-crystalline polyamide having a melting point Tm-2 or an amorphous polyamide having a glass transition point Tg-2, wherein Tm-2 and Tg-2 together are denoted as T-2 and T-2 is at least 20° C. lower than T-1, (b) a stabilizing system comprising a thermostabilizer selected from the group consisting of phenolic thermostabilizers, organic phosphites, aromatic amines, metal salts of elements from Group IB, MB, III and IV of the Periodic Table and metal halides of alkali and alkali earth metals, and combinations thereof, and (c) a metal oxide, or salt thereof, of a transition metal element from Group VB, VIIB, VIIB and VIIIB of the Periodic Table, or a mixture thereof.