5-Hydroxytryptophan (5-HTP) is a naturally occurring amino acid and a direct precursor to serotonin, a key neurotransmitter involved in regulating sleep and mood. Recently, 5-HTP supplementation has emerged as a potential non-pharmacological strategy to improve sleep quality and positively influence gut health, particularly in older adults. Its dual impact on sleep and the gut microbiota highlights a promising avenue for holistic interventions that leverage the gut-brain axis.
Protocols Studied in Research
The Impact of 5‑Hydroxytryptophan Supplementation on Sleep Quality and Gut Microbiota Composition in Older Adults [1]
- Protocol: In this single-blinded, 12‑week parallel randomized controlled trial, 30 older adults (mean age 66 ± 3 years) in Singapore were randomized to receive either 100 mg of 5‑HTP daily or no supplementation. Sleep quality was evaluated every 4 weeks using both subjective measures (Pittsburgh Sleep Quality Index yielding a Global Sleep Score, with >5 indicating poor sleep) and objective assessments (actigraphy). Blood serotonin, urine melatonin, gut microbiota composition, and stool short chain fatty acids (SCFA) were measured at baseline and week 12.
- Outcome: 5‑HTP supplementation significantly improved certain sleep quality components, particularly among poor sleepers who experienced a notable improvement in their Global Sleep Score (ΔSL5‑HTP: -2.80 ± 1.10, p = 0.005). Additionally, these participants exhibited increased microbiota diversity (Simpson index increase of 0.037 ± 0.032 vs. a decrease in controls, p_interaction = 0.013) and a higher relative abundance of SCFA‑producing bacteria, alongside elevated serum serotonin levels.
Research Interpretation: Summary and Conclusion
In a 12-week randomized controlled trial conducted in Singapore, older adults receiving 100 mg of 5-HTP daily experienced significant improvements in sleep quality, especially among those who were poor sleepers at baseline. These participants showed a notable reduction in their Global Sleep Score, alongside increased gut microbiota diversity and a higher relative abundance of short chain fatty acid-producing bacteria, as well as elevated serum serotonin levels.
In simple terms, this study suggests that 5-HTP supplementation can effectively enhance sleep quality and support a healthier gut microbiome in older individuals.
Publications
[1] Sutanto CN, Xia X, Heng CW, Tan YS, Lee DPS, Fam J, Kim JE. The impact of 5-hydroxytryptophan supplementation on sleep quality and gut microbiota composition in older adults: A randomized controlled trial. Clin Nutr. 2024 Mar;43(3):593-602. doi: 10.1016/j.clnu.2024.01.010. Epub 2024 Jan 17. PMID: 38309227.
