Metformin works by decreasing the production of glucose (sugar) by the liver and increasing the insulin sensitivity of body tissues. This means that more glucose is absorbed by cells in the body and converted into energy, and the amount of insulin in the blood is also reduced.
Metformin is sometimes prescribed to women with PCOS to regulate menstrual cycles as it has been shown to lower levels of testosterone and other androgen hormones (which are the primary causes of PCOS). There is no research to support the use of metformin to facilitate weight loss. Women suffering from insulin resistance may experience weight loss when taking metformin as a result of their bodies being better able to process glucose.
UK and international clinical guidelines do not recommend metformin as a first-line treatment, if at all, except in cases of extreme insulin resistance. Recommended treatment options include lifestyle modifications independent of medication, or clomiphene as a drug-based alternative.
- "Metformin therapy for the management of infertility in women with polycystic ovary syndrome" (PDF). Scientific Advisory Committee Opinion Paper 13. Royal College of Obstetricians and Gynaecologists. Archived from the original (PDF) on 2009-12-18. Retrieved 2009-12-13.
- "Metformin Hydrochloride". The American Society of Health-System Pharmacists. Archived from the original on 24 December 2016. Retrieved 2 January 2017.