L-theanine
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Scientific evidence
Outcome-specific summaries with linked references or labelled research searches; review status is shown.
Professional perspectives
None published. Future perspectives require credential review; no verified professional badge is assigned automatically.
Member anecdotes
Personal experiences and questions, never clinical evidence or proof of safety or benefit.
Sponsored content
Must be visibly labelled and remains separate from evidence scores and independent rankings.
Goals & evidence
Marketing targets are not validated outcomes. Review status is shown on each summary; investigated doses are not personal recommendations.
Verified guidance · scientific evidence
Traceable source links; not personalized medical advice.
Human RCTs / systematic reviews
Evidence summary & quality
Some small human trials; certainty and findings vary by outcome
Evidence applies to a specific ingredient, form, population and outcome—not automatically to this product.
Relevant studied outcomes
Relaxation and attention have been investigated, particularly alongside caffeine. Evidence for sleep and anxiety outcomes remains uncertain.
How it might work
Proposed effects on neurotransmission remain under investigation; a plausible pathway does not prove clinical benefit.
Important limitation
Combination results do not establish theanine-alone effects. Small studies are not proof of treatment benefit for anxiety, ADHD or insomnia.
Typical investigated dose / label context
Small trials have investigated varying amounts, often around 100–400 mg and with different caffeine pairings. The sample contains 100 mg; this is not a recommendation.
Not dosing advice. Do not start, stop or change a supplement based on this summary. Confirm suitability and total intake with a qualified healthcare professional.
Safety & interactions. Potential additive effects with sedating or blood-pressure medicines need professional review. Safety in pregnancy, nursing and alongside all medicines is not established here.
Questions to ask a clinician or pharmacist
- Would combining this with caffeine, sedatives or blood-pressure medicines create concerns for me?
- Is the studied ingredient form and amount comparable with this label?
- Could this interact with my medicines, health conditions, pregnancy, nursing, or planned surgery?
- What would we use to judge benefit, and when should I stop or seek advice?
Read the sources
Reference pages and clearly labelled research searches. A search result is not a selected or endorsed paper.
- L-theanine trials/reviews by outcome
PubMed · Research search — not a specific paper or verified citation
What it is
An amino acid from tea, often paired with caffeine.
What to compare
- Pure L-isomer vs. racemic
- Independent third-party testing (identity, potency, heavy metals, microbes)
- Cost per matching active mg, not per capsule
- Tolerability and known side effects at this dose
Evidence grade: Moderate
Caffeine + theanine combination has small acute studies; effects alone are modest. Grades are qualitative editorial summaries, not formal systematic reviews.
Best-in-class candidates
Entered by you, stored only in this browser. Not verified.
Ranking weights (30 / 30 / 25 / 15)
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