I had to go to a dr that specializes in HRT for men and women. I think that some gyno's also can do the blood work to determine your hormone levels. I didn't used to have PMS symptoms, but over the last several years they have gotten worse. My blood work showed my progesterone and DHEA levels were very low. My estrogen and testosterone were also a little low. My doctor initially put me on oral bio-identical progesterone, but because I didn't want to do anything to upset my GI tract, I asked him to prescribe the cream (the cream can also include the estrogen, testosterone, etc.) that you can apply once or twice daily. I noticed a HUGE improvement in my mood (less irritability, less tense, less sad) within just a few days. I (and my family) wished I had done this YEARS ago. It really has made such a difference. The last couple of months I have only had minor PMS for just a few days before. Depending on your symptoms, you could either be low in estrogen or progesterone as they manifest differently.