Supplement
Supports broad cellular function with category-specific mechanisms.[1708,2346,2377, etc.]
Superscript reference numbers link to the Sources bibliography.
Composite Rating
Blends evidence depth, community direction, safety friction, and completeness.
Evidence Intensity
100/100
High depth from human/RCT/meta counts
Community Direction
10
Mixed / Neutral • confidence Minimal
Safety Friction
100/100
High signal from adverse/interaction markers
Data Completeness
100%
Studies 13 • mentions 4 • links 23
Not medical advice. This product is for educational and informational purposes only. It does not diagnose, treat, cure, or prevent any disease and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider with any questions regarding a medical condition.
FDA disclaimer: These statements have not been evaluated by the Food and Drug Administration. Dietary supplements are not intended to diagnose, treat, cure, or prevent any disease. Results may vary. Not intended for use by pregnant or nursing women, individuals under 18, or those with known medical conditions without physician consultation.
If you are experiencing a medical emergency, call 911 or your local emergency number immediately.
Goal alignment: Longevity, Metabolic Health, Energy.[543,691,915, etc.]
Dose guide: Human-study daily dose: 1000 mg-5000 mg/day (higher-confidence extraction from PubMed abstracts)..[543,691,915, etc.]
Category
Other
Evidence Tier
HIGH
Daily Guide
Human-study daily dose: 1000 mg-5000 mg/day (higher-confidence extraction from PubMed abstracts).
Clinical Depth
Humans: 242 • RCTs: 34 • Meta: 2
Cohort / Real-World
Cohort signals: 0
Safety Markers
Adverse signals: 216 • Interactions: 673
Freshness, trend, and study timeline for this item
Status
Trend
→ Stable evidence base
Depth
693 total studies · 5 recent
Timeline
Animal-only studies
2,037
In vitro / tissue
746
Total indexed
693
Interaction signals
673
Human studies
242
Safety adverse signals
216
Weighted direction score: 10 (Mixed / Neutral)
High when >=2 human meta-analyses, or >=5 human RCTs with substantial human literature volume.
Animal-only studies
2,037
In vitro / tissue
746
Total indexed
693
Interaction signals
673
Human studies
242
Safety adverse signals
216
Randomized trials
34
Meta-analyses
2
Distribution of evidence by study design strength
Evidence Strength: High
Composite of study volume, RCTs, and meta-analyses
PMID 33942088 • 2022 Jan 10
The impact of tryptophan supplementation on sleep quality: a systematic review, meta-analysis, and meta-regression.
Nutr Rev
Open PubMedPMID 29138359 • 2017 Nov
Comparative effects of intraduodenal amino acid infusions on food intake and gut hormone release in healthy males.
Physiol Rep
Open PubMedPMID 16948779 • 2006 Oct
Regression of gastroesophageal reflux disease symptoms using dietary supplementation with melatonin, vitamins and aminoacids: comparison with omeprazole.
J Pineal Res
Open PubMedPMID 25112175 • 2014 Sep
Tryptophan supplementation and postoperative delirium--a randomized controlled trial.
J Am Geriatr Soc
Open PubMedPMID 2693995 • 1989
Effects of l-tryptophan and various diets on behavioral functions in essential hypertensives.
Neuropsychobiology
Open PubMedPMID 38591144 • 2024 Jun 1
Oral tryptophan activates duodenal aryl hydrocarbon receptor in healthy subjects: a crossover randomized controlled trial.
Am J Physiol Gastrointest Liver Physiol
Open PubMedPMID 25297614 • 2014
Time-dependent effects of L-tryptophan administration on urinary excretion of L-tryptophan metabolites.
J Nutr Sci Vitaminol (Tokyo)
Open PubMedPMID 38996913 • 2024 Sep
Intraduodenal calcium enhances the effects of L-tryptophan to stimulate gut hormone secretion and suppress energy intake in healthy males: a randomized, crossover, clinical trial.
Am J Clin Nutr
Open PubMedPMID 32272859 • 2021
A systematic review of the effect of L-tryptophan supplementation on mood and emotional functioning.
J Diet Suppl
Open PubMedPMID 38471012 • 2024 Jun 1
Gut Microbiota-Tryptophan Metabolism-GLP-1 Axis Participates in β-Cell Regeneration Induced by Dapagliflozin.
Diabetes
Open PubMedPMID 29468141 • 2018
Impact of the Gut Microbiota on Intestinal Immunity Mediated by Tryptophan Metabolism.
Front Cell Infect Microbiol
Open PubMedPMID 38480886 • 2024 Apr
Dopamine receptor D2 confers colonization resistance via microbial metabolites.
Nature
Open PubMedPMID 40611146 • 2025 Jul 3
Amino acid transporter LAT1 (SLC7A5) promotes metabolic rewiring in TNBC progression through the L-Trp/QPRT/NAD(+) pathway.
J Exp Clin Cancer Res
Open PubMedBenefit reports: 2
Adverse reports: 1
No-effect reports: 1
Mixed reports: 0
Unclear reports: 0
Signal confidence: 0.00
Benefits
Adverse
No Effect
Insufficient empirical signal for a directional adjustment.
Reddit evidence: 0 mentions (confidence 0.00).
Amazon signal: 0 products scanned (confidence 0.00).
GNC signal: 0 products scanned (confidence 0.00) [ERROR].
terminated
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Fallback search failed: Failed to fetch after retries: https://old.reddit.com/search.json?raw_json=1&sort=comments&t=all&limit=16&q=%22l-tryptophan%22%20(supplement%20OR%20capsule%20OR%20powder%20OR%20experience%20OR%20results%20OR%20side%20effects)
Broad search failed: Failed to fetch after retries: https://old.reddit.com/search.json?raw_json=1&sort=new&t=all&limit=16&q=l-tryptophan
Use adverse/interactions PubMed signal counts for screening; perform clinician review before high-dose or multi-drug stack use.
Human-study daily dose signal: 1000 mg-5000 mg/day (confidence HIGH).
Extracted from 7 dosing mentions across 5 PubMed studies (mg/day).
Imported legacy community score: 7.0/10 (heuristic mapping confidence 1.00).
Imported legacy monthly cost signal: ~$15.00.
Legacy community note: Popular for skin and joint health. Users report more hydrated skin and reduced joint stiffness. Often stacked with collagen for synergistic beauty benefits. Topical HA also widely used.
Sentiment Score
-0.3/100
Benefit Mentions
No benefit mentions recorded.
Adverse Mentions
No adverse mentions recorded.
Best Responders
No responder profile recorded.
aggregate • benefit
Aggregate community signal: 4 directional mentions (benefit 2, adverse 1, no-effect 1, mixed 0).
Open mentionamazon
Amazon search for L-tryptophan
Rating: n/a | Reviews: n/a
Open productEvidence Sources
Community Sources
PUBMED • Humans + preclinical triage
Counts aggregated from automated literature sweep and tiering rules.
Outcome: Tier HIGH; humans 242, RCTs 34, meta-analyses 2.[1708,2346,2377, etc.]
Open sourcePUBMED • 2022 • Human evidence curation set
PMID 33942088 from Nutr Rev.
Outcome: See linked PubMed abstract for methods and outcomes.[1708,2346,2377, etc.]
Open sourcePUBMED • 2017 • Human evidence curation set
PMID 29138359 from Physiol Rep.
Outcome: See linked PubMed abstract for methods and outcomes.[1708,2346,2377, etc.]
Open sourcePUBMED • 2006 • Human evidence curation set
PMID 16948779 from J Pineal Res.
Outcome: See linked PubMed abstract for methods and outcomes.[1708,2346,2377, etc.]
Open sourcePUBMED • 2014 • Human evidence curation set
PMID 25112175 from J Am Geriatr Soc.
Outcome: See linked PubMed abstract for methods and outcomes.[1708,2346,2377, etc.]
Open sourcePUBMED • 1989 • Human evidence curation set
PMID 2693995 from Neuropsychobiology.
Outcome: See linked PubMed abstract for methods and outcomes.[1708,2346,2377, etc.]
Open sourcePUBMED • 2024 • Human evidence curation set
PMID 38591144 from Am J Physiol Gastrointest Liver Physiol.
Outcome: See linked PubMed abstract for methods and outcomes.[1708,2346,2377, etc.]
Open sourcePUBMED • 2014 • Human evidence curation set
PMID 25297614 from J Nutr Sci Vitaminol (Tokyo).
Outcome: See linked PubMed abstract for methods and outcomes.[1708,2346,2377, etc.]
Open sourcePUBMED • 2024 • Human evidence curation set
PMID 38996913 from Am J Clin Nutr.
Outcome: See linked PubMed abstract for methods and outcomes.[1708,2346,2377, etc.]
Open sourcePUBMED • 2021 • Human evidence curation set
PMID 32272859 from J Diet Suppl.
Outcome: See linked PubMed abstract for methods and outcomes.[1708,2346,2377, etc.]
Open sourcePUBMED • 2024 • Human evidence curation set
PMID 38471012 from Diabetes.
Outcome: See linked PubMed abstract for methods and outcomes.[1708,2346,2377, etc.]
Open sourcePUBMED • 2018 • Human evidence curation set
PMID 29468141 from Front Cell Infect Microbiol.
Outcome: See linked PubMed abstract for methods and outcomes.[1708,2346,2377, etc.]
Open sourcePUBMED • 2024 • Human evidence curation set
PMID 38480886 from Nature.
Outcome: See linked PubMed abstract for methods and outcomes.[1708,2346,2377, etc.]
Open sourcePUBMED • 2025 • Human evidence curation set
PMID 40611146 from J Exp Clin Cancer Res.
Outcome: See linked PubMed abstract for methods and outcomes.[1708,2346,2377, etc.]
Open source