Date of Award


Degree Type

Selective Evidence-Based Medicine Review

Degree Name

Master of Science in Health Sciences - Physician Assistant


Physician Assistant Studies

Department Chair

John Cavenagh, MBA, PhD, PA-C


OBJECTIVE: The objective of this selective EBM review is to determine whether or not tryptophan is effective in improving sleep in healthy individuals with mild sleep disorders.

STUDY DESIGN: Systematic review of three published, randomized controlled trials (double-blind, placebo-controlled) between 2005-2010, all English language.

DATA SOURCES: Three randomized controlled trials published between 2005 and 2010 were found using PubMed/MEDLINE and Cochrane databases.

OUTCOMES MEASURED: Improved sleep quality and duration of sleep, which were measured using sleep diaries and sleep study questionnaires.

RESULTS: The first study, Cubero et al showed that administration of diet containing high levels of tryptophan reflected more hours of sleep (~7.68 h) as compared to the control (~6.77 h). Hudson et al report a 13.3% increase in total sleep time with pharmaceutical tryptophan added to carbohydrates as compared to 5.5% increase in total sleep time with foods that have naturally high content of tryptophan. The duration of sleep measured in the Shell et al study showed an increase of 6.83 h as compared to 5 h in the control group. No serious adverse events were noted in any of the three studies.

CONCLUSIONS: All three studies reported increases in the duration of sleep and improved sleep quality when tryptophan was included in each trial. This suggests that indeed tryptophan is effective in improving sleep in healthy individuals with mild sleep disorders with little adverse reactions from the added tryptophan.