The fundamental difference between soy isoflavones and progesterone is that one is an estrogen and the other is a progestin. Soy isoflavones are natural phytoestrogens, while progesterone is a progestin, and their effects are completely different. Progesterone relieves the contraction of the smooth muscle of the uterus and causes the endometrium to appear thickened. Soy isoflavones are mainly supplemental phytoestrogens, and are mostly used as an adjunctive treatment for hot flashes, excessive sweating and emotional instability in post-menopausal or menopausal women, so there is a fundamental difference between the two. It is recommended that no matter which one is used, it should be applied under the guidance of a doctor, mainly because it is suitable for you and can achieve effective treatment purposes for the disease.