Loading…
We use essential cookies (authentication, your saved goals/stack) by default. With your permission we'll also enable privacy-respecting analytics (Vercel Web Analytics, anonymous load-time metrics) and error-replay diagnostics (Sentry — DOM snapshots only when an error fires) so we can fix bugs faster. Learn more
Head-to-head evidence comparison — which supplement is right for you?
L-Theanine wins 3 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Likely helps
6 of 7 studies with measurable effects showed benefit.
Top outcomes
Verdict
Likely helps
3 of 4 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (1)
Outcomes where both 5-HTP and L-Theanine have evidence — compare verdict strength side-by-side.
50-100mg for sleep; 150-300mg for mood
For sleep: 30-45 minutes before bed, For mood: 2-3 divided doses with meals
Capsules
100-200mg
Morning with coffee for focus, Evening for relaxation, As needed for stress
Suntheanine® capsules or powder
2-4 weeks
1-2 weeks
2-4 weeks
First 1-2 weeks
30-60 minutes
30-60 minutes
30-60 minutes
Varies
Early pharmacological interventions for universal prevention of post-traumatic stress disorder (PTSD)
The Cochrane database of systematic reviews (2022) · Systematic review · n=2023
This review provides uncertain evidence only regarding the use of hydrocortisone, propranolol, dexamethasone, omega-3 fatty acids, gabapentin, paroxetine, PulmoCare formula, Oxepa formula, or 5-hydroxytryptophan as universal PTSD prevention strategies.
Combination pharmacotherapy for the treatment of fibromyalgia in adults
The Cochrane database of systematic reviews (2018) · Systematic review · n=1474
Two studies only reported any primary outcomes of interest (patient-reported pain relief of 30%, or 50%, or greater).
The Impact of 5-Hydroxytryptophan Supplementation on Cognitive Function and Mood in Singapore Older Adults: A Randomized Controlled Trial
Nutrients (2025) · Rct · n=30
Results: A significant time effect was observed in the MoCA score, which was mainly explained by a significant increase in the 5-HTP group (week 0 vs. week 12: 26.6 ± 1.4 a.u. vs. 27.6 ± 1.4 a.u., p < 0.05).
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).
Limited evidence from small RCTs (n=30, n=166). Effectiveness constrained by mixed study populations and preliminary findings. Higher doses associated with increased nausea risk.
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.
AI-estimated from published studies. Interpret as directional guidance.
L-Theanine has a higher evidence score (9/10 vs 8.5/10) and wins in 3 of 3 categories.
For reduce anxiety & stress, L-Theanine has a higher relevance score (85 vs 60).
No known interactions between 5-HTP and L-Theanine have been documented in our database. However, always consult a healthcare provider before combining supplements.