About to start Letrozole myself today and asked both on here and my medical oncologist about what to do to counter this. The medical oncologist said Fish oil. Several ladies on this site say they take powdered Magnesium daily . There are a lot of other suggestions on this blog and several are/ have been on letrozole - have a look back thru recent blogs .Guess your bone density has been checked - I have osteoporosis and am to have 6 monthly Prolia injections to help counter bone thinning.I joined a gentle exercise class twice a week and if it ever stops raining hope to walk for 30 minutes daily.Thinking of you