Flaxseed supplementation in patients with PCOS could improve some biochemical and anthropometric markers, at least partially, through amelioration of dyslipidemia, obesity, IR, and inflammation. The results indicated a significant decrease in body weight (P = 0.001), waist circumference (P = 0.007), BMI (P = 0.001), insulin concentration (P = 0.021), Homeostatic Model Assessment of Insulin Resistance (P = 0.034), TG (P = 0.013), and leptin (P = 0.007) and a significant increase in HDL-C (P < 0.001) and adiponectin (P = 0.017) in the flaxseed group compared to the control group. This evidence concerns the gene LEP and obesity due to melanocortin 4 receptor deficiency.