Progesterone (P4) is a medication and naturally occurring steroid hormone. It is a progestogen Progesterone is well-tolerated and often produces few or no side effects. . Suppositories, 200, 400 mg, Cyclogest .. Oral: Capsules: Prometrium (100 mg, 200 mg, 300 mg); Vaginal: Tablets: Endometrin (100...