Natural progesterone is bio-identical to what our bodies produce. I used it before I got my mirena out and it helpe sooo much. Then I found out about the mirena issues. The reason I found out about the mirena was I was concerned about mixing the synthetic (what's in mirena) and the natural. It was then when I found this forum. My whole intention was to get the mirena out and continue with the cream. From the research I found, believe it or not the poison in the mirena actually caused estrogen dominance leaving your body low in progestrone. I saw some here say others had bad reactions to it, but couln't actually find any posts on it. I know that you need to figure out the correct dosage or you can feel bad. A good way to know is if you start having insomnia, cut back. Split the dosage in half and apply 1/2 in am & 1/2 in pm. Also, don't always apply in the same spot. Rotate inner thihgs, forearms, and chest