Let’s talk about polycystic ovary syndrome first.
Normally the ovaries produce estrogen, progesterone, and only a small amount of testosterone. But between 4% and 7% of women produce too much testosterone. These women have a pattern of symptoms called polycystic ovary syndrome.
With too much testosterone, the eggs are not always released from their follicles in the ovaries. The ovaries appear to contain cysts because the fluid-filled follicles don't always open and empty.
Women with polycystic ovary syndrome may have problems with fertility because egg release (ovulation) does not always occur. With the abnormal hormone balance, periods can be irregular and the uterus has a higher risk for forming a cancer. Polycystic ovary syndrome can also cause cosmetic effects such as acne and facial hair growth.
Finally, many women with polycystic ovary syndrome also have high levels of insulin and resistance to insulin's effects. This puts them at risk for developing diabetes. Diabetes medicines that reduce insulin resistance, such as metformin, can also help to treat polycystic ovary syndrome.
Metformin (brand name Glucophage) helps to lower blood sugar and also lower insulin levels by:
But it almost never leads to an abnormally low sugar in people with or without diabetes. (This is true if metformin is not being used at the same time as other treatments for diabetes.)
Common side effects of metformin use include:
Metformin is safe for most people, although anyone with kidney failure or liver disease should avoid it. In rare cases, metformin leads to a build-up of lactic acid in the blood.
Metformin can decrease testosterone levels, and may help to restore normal menstrual cycles and fertility.