Common hormone replacement therapies are Premarin (horse estrogen) and Provera (a synthetic progesterone). Premarin has significant side effects, including higher risk of heart attack, inflammation, stroke, and female cancers. Provera causes weight gain, facial hair, and depression. However, bioidentical hormone therapy may not have the same risks. These are human or bioidentical hormones, which are usually much better tolerated with fewer side effects and risks.