Progestins are medications that contain a lab-made form of the hormone progesterone. They have several uses, including preventing pregnancy, treating irregular menstrual cycles, and as part of menopausal hormone therapy. Examples include medroxyprogesterone (Depo-Provera, Provera), norethindrone (Errin, Aygestin), and levonorgestrel (Plan B One-Step, Next Choice). Unlike other progestines, megestrol (Megace ES) is also approved to increase appetite in certain people.