There is little evidence of good quality to support the use of metformin for hirsutism or acne in women or adolescents with PCOS. One review found no statistically significant difference between metformin regimens and co-cyprindiol for controlling hirsutism or effects on acne; another found metformin to be no better than placebo at reducing hirsutism scores. High quality trials specifically investigating the effects of metformin on acne in PCOS are lacking. The Endocrine Society suggests hormonal contraceptives for the first-line pharmacological treatment of hirsutism and acne in the majority of adults and adolescents with PCOS.
As metformin is not licensed for the treatment of PCOS, the prescriber takes full responsibility when prescribing it for PCOS.