I also had hair thinning and nail splintering. My hair is straighter, but not falling out. The nail splintering comes and goes. The worst HU side effect involved my bathroom, luckily my gut finally adjusted after a year. I never had any symptoms of ET Jak2, just elevated platelets that sent me for further testing. I just hope HU doesn't hurt my brain or organs. Recently I had my second shingles shot which might have lowered my platelets to almost bottom level of "normal" range. I also take baby aspirin. Don't want any clots causing stroke or heart attack