Circulatory antioxidant and oxidative stress markers are in correlation with demographics but not cognitive functions in multiple sclerosis patients

•Oxidative stress (OXS) is a major basis of the pathogenesis of MS.•Neither endogenous antioxidant factors including catalase activity (CAT), glutathione peroxidase 1 and 2 (GPX1, GPX2), reduced glutathione (GSH), total antioxidant capacity (TAC), and superoxide dismutase (SOD) nor malondialdehyde (MDA), as an OXS biomarker, are associated with the cognitive function or physical disability in MS patients.•The level of CAT and TAC in male MS patients is higher than in females. Type of MS is associated with levels of GPX1, 2, and SOD.