ForCDurbin: I am a 75 year old female and have been on HU for a year. I don't think there is a "magic number" for HU. I take 1000mg and alternate daily with 1500mg. I have had no side effects except fatigue, which is a problem, but better than the alternative of stroke or heart attack. I have no hair loss or other worrisome side effects. It was worth taking HU for me but everyone's body reacts differently to meds. Only you can determine if it's worth it for you.