Hi Karen, I'm picking up some desmopressin from the chemist today to see if it will help me. I know it's a prescription drug but I've managed to get them to order it in for me. I haven't been diagnosed with diabetes insipidus as I can't seem to get a doctor to do any tests for me so I have to try things myself instead. I'm just wondering how much you should start by taking and how long does it take to have an effect? It's just so that I can see if it will help me, if it doesn't, at least I tried! Thanks for all your help so far.