Disclosed is a molded or extruded thermoplastic article including a polyamide composition including (a) a polyamide resin having a melting point and/or glass transition; (b) 0.1 to 10 weight percent of one or more polyhydric alcohols having more than two hydroxyl groups and having a number average molecular weight (M
n ) of less than 2000; (c) 0.1 to 3 weight percent of one or more co-stabilizer(s) selected from the group consisting of secondary aryl amines and hindered amine light stabilizers, and mixtures thereof; (d) 10 to 60 weight percent of one or more reinforcement agents; and (e) 0 to 50 weight percent of a polymeric toughener including a reactive functional group and/or a metal salt of a carboxylic acid; wherein 4 mm test bars prepared from said polyamide composition, exposed at a test temperature at 170 °C for a test period of 500 hours have a retention of tensile strength, on average, of at least 50 percent, as compared with that of unexposed control of identical composition and shape. Further disclosed is a molded or extruded thermoplastic article, including a thermoplastic polyamide composition, wherein 4 mm test bars of said thermoplastic polyamide composition, when exposed at 210 °C for a test period of 500 hours, have a retention of tensile strength of at least 70 percent. Disclosed is a molded or extruded thermoplastic article including a polyamide composition including (a) a polyamide resin having a melting point and/or glass transition; (b) 0.1 to