Polycystic ovary syndrome (PCOS), which is associated with hyperinsulinaemia, hyperandrogenaemia, impaired glucose metabolism and aberrant adipokines production from the adipose tissue, is a heterogeneous reproductive and endocrine disorder.Currently, metformin, a classical and common insulin sensitizer that can reduce both hyperinsulinemia and hyperandrogenemia, is widely used for patients with PCOS. SGLT-2 inhibitor, a novel glucose-lowering medication, have been shown to have positive effects on reducing body weight, blood pressure and cardiovascular events in individuals with diabetes mellitus. However, evidences related to its management in non-diabetic PCOS women are limited. Hence, we want to give canangliflozin combined with metformin to women with PCOS to see its effect on insulin resistance.

Inclusion Criteria:

1. Female aged 18- 45 years old;
2. Diagnosed criteria meet the Rotterdam criteria (2003);
3. Insulin Resistance

Exclusion Criteria:

1. Women who are pregnant or have a pregnancy plan within six months;
2. Confirmed diagnosis of diabetes.
3. Congenital adrenocortical hyperplasia;
4. Hyperprolactinemia;
5. Hyperthyroidism or hypothyroidism;
6. Combined with liver or kidney diseases;
7. Abnormal liver function (≥ 3 times of the upper limit of normal range);
8. Abnormal renal function (GFR<60ml/min/1.73m2);
9. Adrenal or ovarian tumors secreting androgens;
10. Used metformin, glucagon-like peptide-1 receptor agonists, pioglitazone and contraceptives in the last 3 months.