Hi Claire, I've been on Ribociclib (and Letrozole) since Nov 18 now. The first 5-6 months with the Ribo's were very much trial and error. I started on 600mg, then down to 400mg, now settling on 200mg very successfully so far. I must say the first few months, I thought this "new life" was just going to be super awful given all the side effects I was getting. However, I can now say, I'm doing ok and I've found my "happy place" on the drugs. Please do work with your Onco on the Ribo dosage, it can take a while to find your "happy place" after a bit of trial and error and various side effects may arise (and not necessarily the same ones - I have diff side effects on the diff dosages). The other thing, during 1 cycle, I did dip into a deep depression for a week during the rest week - we think that may have been the Letrozole "taking over" and my body adjusting - I've not had it again since yet, fingers crossed. Please google the Ribo and Letrozole side effects that "may" happen (its very long list) and discuss with your Onco... Best of luck with your journey. Cheers :)