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J Psychiatr Res. 1982-1983;17(2):107-13.

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.

[Indexed for MEDLINE]

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