Progesterone has been clearly shown to play a key role in PMS, Perimenopause, and Menopause . It is a precursor to neurotransmitters in the brain that deal with emotion. There is no debate on the effectiveness and benefit of this hormone. Unfortunately many women go on an antidepressant, sleeping aid, or other anxiety reducing medications when all they really need is Progesterone to help supplement their body's dropped levels. A great resource we have for purchase, along with the Progesterone, is the book 'Are Your Hormones Making you Sick?'.