Here is what I do:
Make a shake and drink it before bed.
Make another one and store it in the fridge.
If you wake up in the middle of the night, drink it.
If you don't wake up in the middle of the night...leave the shake and drink it the next day.
IMO that extra sleep is more important than the shake. Don't set an alarm or anything, but if you wake up to pee, have the shake.