A thermoplastic melt-mixed composition comprising: a) 15 to 89.5 weight percent of a polyamide resin selected from Group polyamides having a melting point of at least 230 °C as determined by DSC at a scan rate of 10 °C/min in the first heating scan and taken at the maximum of the endothermic peak, and comprising (aa) 20 to 35 mole percent semiaromatic repeat units derived from monomers selected from one or more of the group consisting of: (i) aromatic dicarboxylic acids having 8 to 20 carbon atoms and aliphatic diamines having 4 to 20 carbon atoms; and (bb) 65 to 80 mole percent aliphatic repeat units derived from monomers selected from one or more of the group consisting of: (ii) an aliphatic dicarboxylic acid having 6 to 20 carbon atoms and said aliphatic diamine having 4 to 20 carbon atoms; and (iii) a lactam and/or aminocarboxylic acid having 4 to 20 carbon atoms; b) 0.50 to 4.0 weight percent of one or more amino acids selected from the group consisting of primary amino acids and secondary amino acids; said amino acid having no hydroxyl groups and no more than one carboxylic acid; c) 0 to 5 weight percent of one or more polyepoxy compound comprising at least two or more epoxy groups; the polyepoxy compound having an epoxide equivalent weight of 43 to 4000 g/equivalent as determined by calculation, or if the polyepoxy compound is an oligomer, by titration using ASTM D1652-11 method; and a number average molecular weight (M n) of less than 8000; d) 10 to 60 weight percent reinforcing agent; e) 0 to 30 weight percent polymeric toughener; and the weight per cents of components a), b), c) d) and e) are based on the total weight of the thermoplastic melt-mixed composition and wherein 2 mm thick test bars, prepared from said melt-mixed composition and exposed at a test temperature of 230 °C for a test period of 1000 hours, in an atmosphere of air, and tested according to ISO 527-2/1BA, have on average, a retention of tensile strength of at least 40 percent, as compared with that of an unexposed control of identical composition and shape. a) 15 to 89.5 weight percent of a polyamide resin selected from Group polyamides having a melting point of at least 230 °C as determined by DSC at a scan rate of 10 °C/min in the first heating scan and taken at the maximum of the endothermic peak, and comprising (aa) 20 to 35 mole percent semiaromatic repeat units derived from monomers selected from one or more of the group consisting of: (i) aromatic dicarboxylic acids having 8 to 20 carbon atoms and aliphatic diamines having 4 to 20 carbon atoms; and (bb) 65 to 80 mole percent aliphatic repeat units derived from monomers selected from one or more of the group consisting of: (ii) an aliphatic dicarboxylic acid having 6 to 20 carbon atoms and said aliphatic diamine having 4 to 20 carbon atoms; and (iii) a lactam and/or aminocarboxylic acid having 4 to 20 carbon atoms; (aa) 20 to 35 mole percent semiaromatic repeat units derived from monomers selected from one or more of the group consisting of: (i) aromatic dicarboxylic acids having 8 to 20 carbon atoms and aliphatic diamines having 4 to 20 carbon atoms; and (i) aromatic dicarboxylic acids having 8 to 20 carbon atoms and aliphatic diamines having 4 to 20 carbon atoms; and (bb) 65 to 80 mole percent aliphatic repeat units derived from monomers selected from one or more of the group consisting of: (ii) an aliphatic dicarboxylic acid having 6 to 20 carbon atoms and said aliphatic diamine having 4 to 20 carbon atoms; and (iii) a lactam and/or aminocarboxylic acid having 4 to 20 carbon atoms; (ii) an aliphatic dicarboxylic acid having 6 to 20 carbon atoms and said aliphatic diamine having 4 to 20 carbon atoms; and (iii) a lactam and/or aminocarboxylic acid having 4 to 20 carbon atoms; b) 0.50 to 4.0 weight percent of one or more amino acids selected from the group consisting of primary amino acids and secondary amino acids; said amino acid having no hydroxyl groups and no more than one carboxylic acid; c) 0 to 5 weight percent of one or more polyepoxy compound comprising at least two or more epoxy groups; the polyepoxy compound having an epoxide equivalent weight of 43 to 4000 g/equivalent as determined by calculation, or if the polyepoxy compound is an oligomer, by titration using ASTM D1652-11 method; and a number average molecular weight (M n) of less than 8000; d) 10 to 60 weight percent reinforcing agent; e) 0 to 30 weight percent polymeric toughener; and