5-HTP daily boosts cognitive health in older Singaporeans

Daily supplementation with 5-hydroxytryptophan (5-HTP) appears to confer cognitive benefits and reduce depression symptoms in older adults in Singapore, according to a study.

After 12 weeks of intervention, cognitive function significantly improved in participants who did vs did not receive 100 mg of 5-HTP every day. The Montreal Cognitive Assessment (MoCA) total score increased from 26.6 at baseline to 27.6 in the 5-HTP arm and from 26.4 to 27.3 in the control arm (p=0.0007 for time effect). Significant effects were observed in the domains of naming (p<0.0001), language (p=0.0003), and abstraction (p=0.007). [Nutrients 2025;17:2773]

The observed cognitive benefit with 5-HTP was accompanied by an increase in serum serotonin levels. Over 12 weeks, mean serotonin levels increased by 45.8 ng/mL in the intervention arm but dropped by 20.2 ng/mL in the control arm.

Supplementation with 5-HTP also reduced depression symptoms, although the effect was not statistically significant. Geriatric Depression Scale (GDS) scores decreased from 1.2 at baseline to 0.6 at week 12 in the intervention arm and from 1.4 to 0.9 in the control arm.

“These findings highlight the potential of 5-HTP as an accessible supplement to promote cognitive function and mental health in the ageing population,” the investigators said.

The effect of 5-HTP on cognitive function and mood may be attributed to enhanced serotonergic signalling in the central nervous system (CNS). “5-HTP can easily cross the blood–brain barrier, effectively increasing serotonin levels and central serotonergic tone,” they noted. [Mol Psychiatry 2013;19:427-432]

Serotonin is crucial in regulating cognitive processes, such as learning, memory, and executive function, particularly in the prefrontal cortex. “An overall increase in MoCA total score can reflect improvements in these domains, possibly mediated by enhanced serotonergic signalling in frontal regions,” the investigators pointed out. [Transl Neurosci 2016;7:35-49]

However, they acknowledged that in the present study, the control group also showed improvements in MoCA total score to a certain degree, warranting caution in the interpretation of results.

Additional long-term studies with a larger sample size are needed to confirm the present data and establish the role of 5-HTP supplementation in enhancing cognitive function and mood in older adults, the investigators said.

A total of 30 Singaporean adults (50 percent female, 90 percent Chinese) aged between 60 and 85 years completed the study. Of these, 15 had been randomly allocated to the group that received daily supplementation with 100 mg of 5-HTP (mean age 66 years) for 12 weeks and the other 15 to the control group that did not receive the intervention (mean age 67 years).

Cognitive function, mood, and cognitive function-related blood biomarkers (amyloid beta [Aβ]40, Aβ42, gamma-aminobutyric acid [GABA], and serotonin) were assessed at baseline and weeks 4, 8, and 12.

Compared with control, 5-HTP supplementation for 12 weeks had no significant effects on anxiety (evaluated using the Geriatric Anxiety Inventory) as well as the plasma levels of Aβ40, Aβ42, and GABA, and the Aβ42/Aβ40 ratio.