The Impact of 5-Hydroxytryptophan Supplementation on Cognitive Function and Mood in Singapore Older Adults: A…
The newest 5-HTP trial had 30 people, no placebo pill, and participants who weren't depressed to begin with — does anything in it apply to someone who actually has depression?
Well-supported by good-quality research. how we score evidence
Caveat on this rating: The rubric score overstates this trial badly. It was single-blinded with a no-supplement control rather than a placebo capsule, so expectancy is uncontrolled; it enrolled 30 people; and the mood change it reports is half a point on a scale where the group started at 1.2 out of 15, which is not clinically interpretable as treating depression. It is included as the most recent randomised 5-HTP evidence that exists, which is itself the point: this is what "current evidence" looks like for 5-HTP.
5-HTP is sold in the US as a dietary supplement under DSHEA. It has never been approved by the FDA to treat depression, anxiety, insomnia, fibromyalgia, or anything else, and no FDA review of safety, purity, or effectiveness precedes it going on sale.
Thirty Singaporean adults averaging 66 years old were randomised to 100 mg/day of 5-HTP or to no supplement for 12 weeks. The 5-HTP group's Montreal Cognitive Assessment score rose about one point (26.6 to 27.6) and its Geriatric Depression Scale score fell from 1.2 to 0.7, with serum serotonin rising; anxiety scores and the other blood biomarkers did not change. The authors themselves flag the small sample and short duration and call the results preliminary — and the baseline depression score of 1.2 on a 15-point scale means these were people with essentially no depression to treat.
Worth asking
The newest 5-HTP trial had 30 people, no placebo pill, and participants who weren't depressed to begin with — does anything in it apply to someone who actually has depression?
Source
The Impact of 5-Hydroxytryptophan Supplementation on Cognitive Function and Mood in Singapore Older Adults: A Randomized Controlled Trial. — Li S, Sutanto CN, Xia X, Kim JE. (2025)
Indexed peer-reviewed journal
Read the source: https://doi.org/10.3390/nu17172773
DOI: 10.3390/nu17172773
How this was scored
- Study design
- Randomised controlled trial
- Funding
- Independently funded
- Published in
- Indexed peer-reviewed journal
- Sample size
- 30
- Preregistered
- Yes
- Conflicts disclosed
- Yes
- Independent of proponent
- Yes
- Retracted
- No
Read the full scoring rubric, including what it can't tell you.
Published August 19, 2026.
Questions
How strong is the evidence behind this?
Resolv rates this source "strong evidence". Well-supported by good-quality research. It scores 80 out of 100 on our published rubric. One caveat travels with that badge: The rubric score overstates this trial badly. It was single-blinded with a no-supplement control rather than a placebo capsule, so expectancy is uncontrolled; it enrolled 30 people; and the mood change it reports is half a point on a scale where the group started at 1.2 out of 15, which is not clinically interpretable as treating depression. It is included as the most recent randomised 5-HTP evidence that exists, which is itself the point: this is what "current evidence" looks like for 5-HTP. The score is calculated from recorded facts about the source — study design, funding, publication venue, sample size, preregistration — not typed in by an editor.
What is the source for this?
The Impact of 5-Hydroxytryptophan Supplementation on Cognitive Function and Mood in Singapore Older Adults: A Randomized Controlled Trial. — Li S, Sutanto CN, Xia X, Kim JE. (2025). Published in: Indexed peer-reviewed journal. DOI: 10.3390/nu17172773. The full source is linked on this page so you can read it yourself.
Who paid for this research, and does that matter?
Study design: Randomised controlled trial. Funding: Independently funded. The researchers were independent of whoever benefits from the result. Industry sponsorship is one of the most reliably measured biases in medicine, which is why funding carries real weight in the score rather than sitting in a footnote.
Is 5-htp, 5-hydroxytryptophan, l-5-htp, oxitriptan, griffonia simplicifolia extract FDA approved for this use?
No. Its current status is: Not FDA-evaluated for this use. 5-HTP is sold in the US as a dietary supplement under DSHEA. It has never been approved by the FDA to treat depression, anxiety, insomnia, fibromyalgia, or anything else, and no FDA review of safety, purity, or effectiveness precedes it going on sale.
Is this medical advice?
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.