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5-HTP and sleep quality: grade C

Limited evidence. Direction: No effect.

C LimitedSingle research groupShort-term only

Educational guidance, not medical advice

Why this grade

Rubric condition met: One single-blinded randomized trial with an untreated control and no placebo, in older adults only; benefit only in a subgroup

The only trial we could assess in people without a sleep diagnosis randomized 30 older adults to 100 mg a day or nothing for 12 weeks, single-blinded with no placebo. The authors report a favorable effect on certain sleep quality components, with the improvement in the global sleep score seen in poor sleepers rather than good sleepers. With no placebo, a subgroup result and one research group, the proposal is C with direction none.

How we grade evidence

Studies this grade rests on

The impact of 5-hydroxytryptophan supplementation on sleep quality and gut microbiota composition in older adults: A randomized controlled trial.

Sutanto CN, Xia X, Heng CW. The impact of 5-hydroxytryptophan supplementation on sleep quality and gut microbiota composition in older adults: A randomized controlled trial Clin Nutr, 2024. PMID 38309227

Result not recorded
Design
Single-blinded, 12-week parallel randomized controlled trial; control group took nothing (no placebo)
Sample
n = 30
Population
Older adults in Singapore (66 ± 3 years)
Funding
National University of Singapore (Crossref funder)

Search and history

Search (): (5-hydroxytryptophan[ti] OR 5-HTP[ti]) AND (sleep[tiab]) AND (randomized controlled trial[pt] OR clinical trial[pt])

  • Graded C (proposed): Proposed in the monograph draft
  • C to C (approved): Editor sign-off November 13, 2026: grade matches the editor-approved final page