Effects of L-tryptophan on sleepiness and on sleep.
Over the past 20 yr, 40 controlled studies have been described concerning the effects of L-tryptophan on human sleepiness and/or sleep. The weight of evidence indicates that L-tryptophan in doses of 1 g or more produces an increase in rated subjective sleepiness and a decrease in sleep latency (time to sleep). There are less firm data suggesting that L-tryptophan may have additional effects such as decrease in total wakefulness and/or increase in sleep time. Best results (in terms of positive effects on sleep or sleepiness) have been found in subjects with mild insomnia, or in normal subjects reporting a longer-than-average sleep latency. Mixed or negative results occur in entirely normal subjects--who are not appropriate subjects since there is "no room for improvement". Mixed results are also reported in severe insomniacs and in patients with serious medical or psychiatric illness.
D004044:Dietary Proteins / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007930:Leucine / Q000494:pharmacology; D008297:Male; D012890:Sleep / Q000187:drug effects*; D007319:Sleep Initiation and Maintenance Disorders / Q000188:drug therapy; D012894:Sleep Stages / Q000187:drug effects; D014364:Tryptophan / Q000008:administration & dosage / Q000494:pharmacology*
D004044:Dietary Proteins; D014364:Tryptophan; D007930:Leucine