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Head-to-head evidence comparison — which supplement is right for you?
Ashwagandha vs L-Theanine: Ashwagandha has the stronger overall evidence (7.5 vs 6/10); they're alternatives for reduce anxiety & stress — the best pick depends on your goals. Take the 60-second quiz for a pick tailored to your goals.
Ashwagandha wins 2 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Likely helps
4 of 4 studies with measurable effects showed benefit.
Top outcomes
Verdict
Too few graded studies
1 of 1 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (2)
Outcomes where both Ashwagandha and L-Theanine have evidence — compare verdict strength side-by-side.
300-600mg daily (standardized extract)
Morning for daytime stress, Evening for sleep support
KSM-66 or Sensoril standardized extract
100-200mg
Morning with coffee for focus, Evening for relaxation, As needed for stress
Suntheanine® capsules or powder
2-4 weeks
2-4 weeks
2-4 weeks
First week
30-60 minutes
30-60 minutes
30-60 minutes
Varies
Effects of Ashwagandha (Withania Somnifera) on stress and anxiety: A systematic review and meta-analysis
Explore (NY) (2024) · Meta analysis · n=558
Significant effect on the Perceived Stress Scale (PSS) (MD = -4.72, 95 % CI = [-8.45 to -0.99]).
Effects of Withania somnifera Extract in Chronically Stressed Adults: A Randomized Controlled Trial
Nutrients (2024) · Rct · n=131
8-week double-blind RCT in adults with self-reported high stress comparing an aqueous root and leaf extract at 125, 250 and 500 mg a day with placebo (131 enrolled, 98 analysed).
Plant-derived nootropics and human cognition: A systematic review
Critical reviews in food science and nutrition (2023) · Systematic review
Bacopa monnieri improves language, learning and memory.
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 points come from one 8-week dose-comparison RCT of an aqueous root and leaf extract at 125, 250 or 500 mg a day against placebo in adults with self-reported high stress (PMID 38732539, 131 enrolled, 98 analysed). All three doses reduced perceived stress and were reported as safe, and the authors describe the effect as dose-dependent. The abstract gives no per-dose effect sizes, so the curve shows only that ordering, not how large each step is. It also does not show whether doses above 500 mg add more. Trials of other extracts (root-only extract at 600 mg a day, PMID 23439798, and a 240 mg extract, PMID 31517876) are not on this axis because milligrams of different extracts are not equivalent.
Single-dose trials of L-theanine alone. In a crossover trial of 27 young adults given 100, 200 and 400 mg (PMID 32777998), only 400 mg shortened the P3b attention signal, and no dose changed reaction time. In a crossover trial of 20 healthy men, 200 mg improved recognition reaction time (PMID 26869148). In a crossover trial, 250 mg alone raised headache ratings and lowered correct serial subtractions, and the benefits came with caffeine (PMID 18006208). Most cognitive gains in this literature are for L-theanine combined with caffeine, which this curve does not show. The 400 mg ceiling rests on an 8-week trial of 80 schizophrenia inpatients, where side effects at 400 mg a day matched placebo (PMID 37697164). No trial found a best dose.
AI-estimated from published studies. Interpret as directional guidance.
Ashwagandha has a higher evidence score (7.5/10 vs 6/10) and wins in 2 of 3 categories.
For reduce anxiety & stress, Ashwagandha has a higher relevance score (95 vs 85).
No documented interaction was found in the data searched. This does not establish that this exact combination is safe.
The honest tier list — proven staples vs situational vs mostly marketing. The hub the other guides feed into.
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Ashwagandha, L-theanine, magnesium, saffron — what actually helps stress, and the safety caveats.
The right pick depends on your goals. Answer a few quick questions for a personalised recommendation — or dig into the full evidence on each.