I have been on Tamoxifen since November of 2013 and will finish my 10 years this coming fall. Not one single side effect. Don't even realise I take it. On another note I wondered how my bone density tests would fare after being on it for so long. I am 71 and had a new evaluation in December and absolutely normal ! No osteopenia and no osteoporosis. I take no other medications. Guess I am one of the lucky ones. Interestingly I had HER 2 positive breast cancer also and was put on Tamoxifen so don't quite understand what the difference is.