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Head-to-head evidence comparison — which supplement is right for you?
L-Theanine and Rhodiola Rosea are closely matched across evidence, studies, and safety.
Verdict
Likely helps
4 of 5 studies with measurable effects showed benefit.
Top outcomes
Verdict
Likely helps
5 of 7 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (2)
Outcomes where both L-Theanine and Rhodiola Rosea 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
200-600mg daily
Morning on empty stomach, Before stressful events
Standardized to 3% rosavins and 1% salidroside
30-60 minutes
30-60 minutes
30-60 minutes
Varies
1 week
1-2 weeks
1 week
First 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).
Efficacy of Pharmacological Interventions in Milder Depression: A Systematic Review and Meta-Analysis
Neuropsychopharmacology reports (2025) · Meta analysis · n=1049
A meta-analysis found no significant difference in response rates between the two treatments (risk ratio [RR] = 0.96, 95% CI: 0.78-1.18) or dropout rates (RR = 1.08, 95% CI: 0.62-1.88).
Rhodiola rosea supplementation on sports performance: A systematic review of randomized controlled trials
Phytotherapy research : PTR (2023) · Systematic review · n=263
Acute supplementation with RR has a positive effect on endurance performance and rating of perceived exertion (RPE).
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.
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 systematic reviews showing anti-fatigue effects. Most studies used standardized extracts (3% rosavins/1% salidroside). Effects observed for both mental and physical fatigue.
AI-estimated from published studies. Interpret as directional guidance.
Both L-Theanine and Rhodiola Rosea are closely matched — the best choice depends on your specific health goals.
For build stress resilience, Rhodiola Rosea has a higher relevance score (92 vs 70).
No known interactions between L-Theanine and Rhodiola Rosea have been documented in our database. However, always consult a healthcare provider before combining supplements.