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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
4 of 5 studies with measurable effects showed benefit.
Top outcomes
Verdict
Mostly mechanism / observational
Top outcomes
Shared outcomes (2)
Outcomes where both L-Theanine and Tyrosine have evidence — compare verdict strength side-by-side.
100-200mg
Morning with coffee for focus, Evening for relaxation, As needed for stress
Suntheanine® capsules or powder
500-2000mg
30-60 minutes before stressful activity, On empty stomach for best absorption
L-Tyrosine powder or capsules
30-60 minutes
30-60 minutes
30-60 minutes
Varies
30-60 minutes
30-60 minutes
30-60 minutes
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).
Tyrosine promotes cognitive flexibility: evidence from proactive vs. reactive control during task switching performance
Neuropsychologia (2015) · Rct · n=22
Tyrosine supplementation improved task switching performance under demanding conditions
Effect of tyrosine supplementation on clinical and healthy populations under stress or cognitive demands: A review
Journal of Psychiatric Research (2015) · Review
Converging evidence for cognitive enhancement under demanding conditions
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 single meta-analysis of 56 participants showing significantly higher blood tyrosine concentrations with supplementation. Clinical significance of elevated blood tyrosine levels for cognitive outcomes remains unclear. Most claimed cognitive effects lack direct study support in the provided evidence.
AI-estimated from published studies. Interpret as directional guidance.
L-Theanine has a higher evidence score (6/10 vs 6/10) and wins in 2 of 3 categories.
For reduce anxiety & stress, L-Theanine has a higher relevance score (85 vs 65).
No known interactions between L-Theanine and Tyrosine have been documented in our database. However, always consult a healthcare provider before combining supplements.