In order of amazingness:
1. Melatonin 0.5-3 mg at bedtime. Start with 0.5 mg at bedtime and increase if not helping. If you wake up with a headache, lower the dose.
2. Tryptophan 500-1000 mg an hour before bedtime. (this raises Serotonin so helps with mood too).
3. Phosphatidylserine 100-300 mg. If you are stressed and not sleeping or waking up in the early hours and having trouble falling back to sleep, cortisol can be the problem. Use Phosphatidylserine with dinner and at bedtime.
All 3 of these supplements improve brain function, and memory.