DHEA is a hormone made from vegetable sources. If you can take it an hour or so before you normally get up, it would be easier to get out of bed. Taking it when you get up seems to be the next best thing. When I know I'm going to get less than four hours of sleep I take it when I go to bed; getting to sleep is usually too easy for me. DHEA is the one that is fairly flexible and easy to use.

Melatonin works best when you are in complete darkness. For that reason, I would guess, having a bright light next to your bed would help to get up in the morning.