I have been on Climara for about 3 weeks. I was prescribed it as I am 39 years old and going through menopause. Other than an increased number of headaches, I have had no negative side effects. It has been a Godsend in relieving my hot flashes and night sweats and I started sleeping through the night after only one week! The unfortunate part of this picture is that this patch is not covered under my health plan so I am seeing the doctor tomorrow to have something else prescribed (probably something oral) which will be covered. I am hoping for the same positive results with an oral version of the estrogen.