I'm on 1000mg HU every other day and 1500mg on opposite days along with 325mg aspirin every day. I was diagnosed with ET about a year ago. I, too, experience fatigue but that's about all (that I can attribute to the meds. All my other issues are due to age and bad luck. I feel that it's worth feeling tired to avoid the stroke or heart attack that my ET could cause. You have to decide what's most important to you and what you are willing to risk. I'm not one to take chances and try to trust my doctors. I hope that you are fortunate enough not to have any other side effects besides fatigue as some others are not.