INS and acne: The secondary outcomes were Total cholesterol, triglyceride, low-density lipoprotein, high-density lipoprotein, fasting glucose, fasting insulin, insulin sensitivity index, body mass index, hypertrichosis score, acne score, adverse reactions, etc. Two reviewers will independently conduct cations retrieval, de-duplication, filtering, quality assessment, and data analysis by Endnote X9.1 and Review Manager software (RevMan V.5.3).