@Dory65 my aches at the start settled after 3 or so months. They tended to be worse in the morning or when too much sitting around.I think from observation on here chemo people may take a bit longer. I found walking an hour daily was a big help in that I could walk thru it after a bit . Re brand differences I guess you mean fillers and coatings . I have been for a year until lately on Sandoz brand from Chemist Warehouse. Sandoz manufactured the firs Letrozole under the name Femara. I know the Chemist King brand made me feel quite low. If you want to give it a go swap brands - there are 8 in Australia - maybe for a couple of months and see how you feel. Also there are other aromatase inhibitors that some members on here have changed to and found easier to live with but I’d wait 6 months before approaching your oncologist on that one.