In a randomized, double-blinded, placebo-controlled crossover trial, compared to placebo, metformin has been shown to significantly reduce body weight, fasting plasma glucose, insulin levels, testosterone, and the homeostatic model assessment of insulin resistance (HOMA) index in obese women with PCOS and BMI ≥ 30. Women with a BMI < 30 also experienced a reduction in insulin levels. The gene discussed is INS; the disease is polycystic ovary syndrome.