I am on it for almost a year. I read it takes about six months or longer to get the dosage correct and that was about right. Started off with 500mg daily and my platelets dropped down too low after about four months. I was having some teeth sensitivity, small brown spots on my skin and hair loss. Went down to five days a week and now currently on three days a week for about four months. Side effects have basically disappeared with the lower dosage. I see my platelets crawling back up and don't want to up the dosage again but time will tell. I just am grateful the medication works and that is it very inexpensive. Do you have PV? or ET? Jak2 positive labs confirmed my PV.