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Key Points
- 5-HTP improved language and executive functions
- Overall MoCA cognitive scores increased significantly
- Serotonin levels rose only in the 5-HTP group
- Depressive symptoms decreased by week 8
- Benefits may stem from enhanced brain signaling
Overview of Methods
Thirty healthy adults (ages 60–85) were randomized into two groups.
- Control Group: 15 participants received no supplement for 12 weeks
- 5-HTP Group: 15 participants received 100 mg/day 5-HTP capsule before bed for 12 weeks
Cognitive Performance Improved
Cognition was measured using the Montreal Cognitive Assessment (MoCA), where higher scores reflect better overall brain function.
5-HTP led to measurable improvements in MoCA scores, even though both groups started at the same baseline.
"A significant time effect was observed in the MoCA total score, which was particularly explained by a significant increase in the 5-HTP group."
Gains were most evident in language, naming, and abstraction, suggesting improvements in language-related and higher-order cognitive skills.
"Additionally, significant time effects were also observed in naming, language, and abstraction."
Mechanistic research on 5-HTP explains how increased central serotonin synthesis supports cognition, mood regulation, and neural signaling pathways.
Serotonin Levels Increased
Blood serotonin saw a 26% increase in the 5-HTP group, while the control group declined over the same period.
- +45.8 ng/mL increase in the 5-HTP group
- –20.2 ng/mL change in the control group
"There was a significant increase in the serotonin levels after 5-HTP supplementation."
Because serotonin plays an important role in memory, learning, and cognitive processing, this increase likely supported the cognitive and mood-related changes observed.
Depressive Symptoms Improved
In the 5-HTP group, participants saw improvements in mood and GDS (Geriatric Depression Scale) for depressive symptoms scores.
"Overall GDS score decreased, with a significant decrease in week 8 only in the 5-HTP group, suggesting a potential benefit of 5-HTP in reducing depression."
This indicates that participants reported fewer depressive symptoms after 8 weeks of taking 5-HTP. The control group did not show this pattern.
Conclusion
This trial provides evidence that low-dose 5-HTP can support cognitive performance and mood in healthy older adults, likely through increased serotonin availability.
Improvements were seen in just 12 weeks in individuals without any cognitive impairments and biomarker and behavioral changes suggest 5-HTP may help maintain brain function during aging.
"5-HTP supplementation demonstrated potential in improving cognitive function and alleviating depression symptoms."
"5-HTP supplementation on cognitive function and mood outcomes may reflect preventive or maintaining benefits… without overt impairment."
Broader research shows age-related changes in neuronal energy metabolism interact to influence cognitive aging trajectories.
Larger, long-term studies will help confirm the overall protective effects of 5-HTP against age-related cognitive markers.
"This finding highlights the promising effect of 5-HTP as an accessible complementary supplementation to promote cognitive function and mental health in the aging population."
