Hi @DearB I have Graves Disease which has responded well to Neomercazole several times since 2004. Currently in remission and, to my surprise, has not been triggered by the BC diagnosis and treatment (Lumpectomy, single mastectomy and started Taxol a couple of weeks ago after 4 X AC 3 weekly) all since August. We add the thyroid function tests to the others 3 monthly and they go to my endo - as she says, 'if it flares up we just start again'. It takes a while for the medication to get things level again, the tests are the best indicator, and once you know what are normal levels for you it really helps. It can be scary when it first happens, I had no idea what it was and my levels were off the page. Good luck!