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Head-to-head evidence comparison — which supplement is right for you?
L-Theanine wins 2 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Likely helps
3 of 4 studies with measurable effects showed benefit.
Top outcomes
Verdict
Likely helps
5 of 6 studies with measurable effects showed benefit.
Top outcomes
100-200mg
Morning with coffee for focus, Evening for relaxation, As needed for stress
Suntheanine® capsules or powder
500-1000mg before bed
30-60 minutes before bed, On empty stomach or with carbohydrates
L-Tryptophan capsules
30-60 minutes
30-60 minutes
30-60 minutes
Varies
30-60 minutes
1-2 weeks
1-2 weeks
1-2 hours after dose
The effects of L-theanine consumption on sleep outcomes: A systematic review and meta-analysis
Sleep medicine reviews (2025) · Meta analysis · n=897
The findings indicate the potential use of L-theanine in the management of sleep disturbances; however, the lack of studies on "pure" L-theanine warrants further investigation.
Efficiency of Different Supplements in Alleviating Symptoms of ADHD with or Without the Use of Stimulants: A Systematic Review
Nutrients (2025) · Systematic review
The evidence revealed the potential use of supplements as complementary ADHD treatments under clinical guidance.
Analysis of the Effects of Known Sleep-Support Supplements in Relation to Life Habits, Sleep Conditions, and Sleep Problems
Nutrients (2023) · Rct · n=160
All the tested supplements were found to ameliorate sleep problems significantly (Analysis 1).
The Tryptophan Catabolite or Kynurenine Pathway in a Major Depressive Episode with Melancholia, Psychotic Features and Suicidal Behaviors: A Systematic Review and Meta-Analysis
Cells (2022) · Meta analysis · n=4647
Severe patients showed significant lower (p < 0.0001) TRP (standardized mean difference, SMD = -0.517, 95% confidence interval, CI: -0.735; -0.299) and TRP/CAAs (SMD = -0.617, CI: -0.957; -0.277) levels with moderate effect sizes, while no significant difference in CAAs were found.
Comparative efficacy and tolerability of nutraceuticals for depressive disorder: A systematic review and network meta-analysis
Psychological medicine (2025) · Meta analysis · n=17437
Adjunctive nutraceuticals consistently showed better efficacy than antidepressants (ADT) alone in outcomes including SMD, remission, and response.
Differential Metabolites in Osteoarthritis: A Systematic Review and Meta-Analysis
Nutrients (2023) · Meta analysis · n=495
In the 13 studies, 132 kinds of small molecule differential metabolites were extracted, 58 increased, 57 decreased and 17 had direction conflicts.
Meta-analysis (n=897) and multiple RCTs support sleep benefits. Studies often used L-theanine in combination with other compounds, limiting pure L-theanine effect attribution. Effects include reduced sleep onset latency and improved subjective sleep quality.
Based on meta-analyses showing tryptophan's role in depression and serotonin pathways. Evidence comes from studies of tryptophan depletion and kynurenine pathway research rather than direct supplementation RCTs. Conservative effectiveness due to indirect evidence.
AI-estimated from published studies. Interpret as directional guidance.
L-Theanine has a higher evidence score (9/10 vs 8/10) and wins in 2 of 3 categories.
For reduce anxiety & stress, L-Theanine has a higher relevance score (85 vs 55).
No known interactions between L-Theanine and Tryptophan have been documented in our database. However, always consult a healthcare provider before combining supplements.