I found that the best time to take Clen is actually RIGHT before you go to sleep. I don't mean take it, then go to bed an hour, or even 10 minutes later. Just keep it bedside, and as you're about to fall asleep take it then.
It's NEVER uninterrupted my sleep this way, and I don't have the shakes nearly as bad as I did when I was taking it as soon as I woke up. It also works just as well.