When do you ovulate on metformin?

Ovulation. Metformin had been used in conjunction with Clomid (clomiphene) to stimulate ovulation in people with pcos. Metformin basically does not induce ovulation, more likely by adjusting Insulin level allows other natural hormones to act and aid ovulation. So if you ovulate under therapy you should ovulate somewhere between 14-16 days from your last menstrual period.