As the amino acid the brain uses to make serotonin, melatonin, and niacin, L-Tryptophan, plays a key role in regulating the sleep wake cycle. Dietary L-tryptophan increases the amount of REM (rapid eye movement) sleep, the stage that involves deep rest and dreaming. If taken within an hour of going to bed, tryptophan reduces the time needed to fall asleep by as much as 50% and enhances the quality and length of sleep.
Most of us eat 1 to 1.5 grams of dietary L-tryptophan daily. Two to four grams have been used clinically to reduce the time required to fall asleep when taken an hour before retiring, but even 500 mg (1/2 gram) can induce sleep. Foods rich in L-tryptophan include: turkey, yogurt, milk, sunflower seeds, peanuts, potatoes, pasta, bread, bananas, cereal, and rice.