For those who take melatonin, one thing I can't find the answer to is, how soon after you wake up can you take a dose?
For example, land on the west coast at midnight, and operate a red-eye that following night. If you wake up at 8-9am, can you pop a melatonin by noon or 1 and hope to sleep until showtime, or is that unrealistic? In theory after a nights sleep, you'd have a 4ish hour window of being awake before trying for another long sleep period.