Stabilized solution-dyed fiber is made by melting a polyamide which is amide monomers polymerized in the presence of at least one mono or dicarboxylic acid chain regulator and at least one hindered piperidine compound, coloring the melted polyamide, and spinning the colored polyamide into fibers that have about 40% or better retained tenacity after 2125 kJ exposure to xenon arc radiatiorl as per AATCC Test Method 16-1993, "Colorfastness to Light," Option E. Copper stabilizers are unnecessary.