Numerous neurological diseases are exacerbated by oxidative stress, including fragile x syndrome (FXS), which occurred as a result of a mutation in the fragile x mental retardation 1 gene (FMR 1-gene). Several studies have found that redox equilibrium is disrupted in the brains of knockout mice with fragile x syndrome, suggesting that antioxidant levels in plasma may reflect the oxidative stress profile in FXS. The goal of this study aimed to evaluate antioxidants biomarker levels in FXS patients indicating that antioxidants can be used as indicators in FXS patients. This study included a total of 60 subjects (30 suspected FXS patients: 15 males and 15 females, while the remaining 30 were healthy subjects). Full blood genomic DNA was used, followed by gel electrophoresis and CGG repeat calculation. Antioxidant biomarkers (total glutathione, glutathione peroxidase, and superoxide dismutase) were measured in the plasma of patients and controls groups. The study revealed that the average levels of antioxidant biomarkers in FXS patients were significantly lower than in controls. FXS and oxidative stress are linked, implying that oxidative stress plays a role in the pathogenic process. Antioxidants may be helpful in the therapy of FXS.