Key takeaways
Clomid (clomiphene) and metformin (Glucophage) are both medications that can be used to address fertility issues, but they belong to different medication classes and have important differences. Clomid is a selective estrogen receptor modulator (SERM) primarily used to treat female infertility by inducing ovulation. It is taken orally for 5 days during the menstrual cycle. Metformin, on the other hand, is a biguanide used mainly to manage type 2 diabetes by lowering blood sugar levels. It is also sometimes used off-label to improve fertility in women with polycystic ovary syndrome (PCOS). Metformin is usually taken once or twice daily with food to minimize stomach upset. Both medications are available as a lower-cost generic. Common side effects of Clomid include hot flashes and stomach pain, whereas metformin often causes diarrhea and nausea. Clomid can cause vision problems and ovarian hyperstimulation syndrome, while metformin can increase the risk of lactic acidosis.
