I started on Letrozole in mid 2017...so almost five years now. I have other preexisting medical conditions which affect the connective tissue throughout my body, blood vessels, kidneys, lungs, stomach and especially my skin, joints and ligaments. I have had no more deterioration in my joints and ligaments than my rheumatologist (and other specialists) would have expected in that five year frame anyhow. I reckon that if I hadn't had these other conditions, I would have not had any appreciable problems with them. I agree with others above...try them and see, and if one doesn't suit, then try another.