And if the "progesterone" in the product really is "natural," it isn't progesterone. In the 1930's, scientists found an easy way to synthesize progesterone from diosgenin, a chemical found in a Mexican yam. Diosgenin is chemically similar to progesterone, and it can be extracted from the yam and turned into progesterone in just a few steps in the lab. These involve baking the yam to dry it out and washing out the diosgenin with acetone, the same toxic chemical used in nail polish remover. The human body cannot bake Mexican yam, and it certainly cannot wash out their chemicals with acetone. The diosgenin in the herb is not transformed into anything the human body can use. Even if the manufacturer says the yam has been micronized so it is easily absorbed, that only means your body can take up useful ingredients all the more quickly. Just say no to "natural" progesterone. The best that will happen is that you will waste your money. The worst that will happen is that you take ground up birth control pills that can undo years of treatment.
Dr. J. T. Hargrove of Vanderbilt University is often cited as the lead researcher in a study of herbal progesterone in the treatment of menopause. This is simply a lie. He and his research team studied the role of micronized (finely ground) synthetic estrogen and progesterone in treating women's issues that do not include PCOS. If you hear of women who do better on natural progesterone than they were doing birth control pills, that is only because they are better off with no treatment at all. Nothing, absolutely nothing of value is to be found in natural progesterone products for women with menstrual irregularity, infertility, PCOS, or any other hormonal condition.