What are Premarin and Provera?
Premarin® (conjugated equine estrogen) is a combination of many hormones obtained from pregnant horses. Provera® is a synthetic progestin that has been chemically altered to mimic human progesterone. Both products (and the combination of the two – Prempro®) were made to try and mimic the estrogens and progesterone made naturally by the human body. The problem is that since they are not completely identical to those made by your body, your body can tell the difference and many women cannot tolerate them due to their significant side effect profile.