Its all up to you. You can use as much or as little water as you want. Just make sure you use enough to get a good measurement on your injects. So sure, with a 10mg vial of GHRP2, 5ml would be good. Every 1/2cc is going to be 1mg. This is going to be easy to break down if you are injecting with 1/2cc insulin pins. For my GH, I mix 1ml of water for a 10iu vial, and split that up into 3 shots. No prolems for me