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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
Mostly mechanism / observational
0 of 1 studies with measurable effects showed benefit.
Top outcomes
Verdict
Likely helps
4 of 5 studies with measurable effects showed benefit.
Top outcomes
300-600mg extract (2.5% ursolic acid)
Morning, With or without food
Standardized extract (leaf)
100-200mg
Morning with coffee for focus, Evening for relaxation, As needed for stress
Suntheanine® capsules or powder
2-4 weeks
2-4 weeks
4-8 weeks
30-60 minutes
30-60 minutes
30-60 minutes
Varies
The Neuroprotective Potential of Ocimum Plant Species: Seasoning the Mind with Sweet and Holy Basil
Nutrients (2025) · Systematic review
This review synthesizes experimental evidence regarding Ocimum species with neuroprotective potential in AD, particularly Ocimum sanctum and Ocimum basilicum.
Modulation of the hypothalamic-pituitary-adrenal (HPA) axis by plants and phytonutrients: a systematic review of human trials
Nutritional neuroscience (2022) · Systematic review
For most phytonutrients, the effects of supplementation on HPA-axis activity in humans is unclear.
Medicinal Plants in the Treatment of Respiratory Diseases and their Future Aspects
Recent patents on biotechnology (2025) · Systematic review
Some medicinal plants, notably Echinacea purpurea and Zingiber officinale, exhibit potential for adjuvant symptomatic therapy in respiratory conditions, such as chronic obstructive pulmonary disease (COPD), bronchitis, asthma, the common cold, cough, and whooping cough.
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).
Based on systematic review evidence of HPA-axis modulation and adaptogenic properties. However, reviewers note that effects on HPA-axis activity in humans remain unclear and require more definitive research. Conservative estimates due to limited human trial data.
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 (6/10 vs 5.5/10) and wins in 2 of 3 categories.
For reduce anxiety & stress, L-Theanine has a higher relevance score (85 vs 80).
No known interactions between Holy Basil and L-Theanine have been documented in our database. However, always consult a healthcare provider before combining supplements.