Have been on letrozole for 18 months. At first I took it in the morning but have changed to the evening, this seems to have helped with the stiffness and muscle aches. I take panadol when needed. My biggest side effect has been bad hot sweats and the feeling of always being warm. I don't go anywhere without airconditioning! They have suggested a very low dose of an antidepressant to help but I'm trying to avoid this. Otherwise it doesn't seemed to have effected my weight and fortunately my bone density is very good but I'll be tested again this year.