L-theanine is the unique amino acid in tea that promotes alpha brain waves, the 'calm focus' state. It works fast (30-60 minutes) and pairs particularly well with caffeine.
The combination improved accuracy on attention-switching tasks and reduced susceptibility to distractor stimuli vs caffeine alone, the canonical 'calm focus' finding.
L-theanine reduced heart rate and salivary IgA responses to acute stress, suggesting attenuation of sympathetic nervous system arousal.
L-theanine significantly reduced acute stress and anxiety in adults exposed to stressors. Chronic supplementation effects were smaller but consistent.
L-theanine improved reaction time and working memory on cognitive tests in attention-prone adults, without sedation.
We prioritize randomised controlled trials and meta-analyses over single observational studies. Animal and in-vitro data are listed as "mechanistic", they suggest direction, not human effect size.
We don't cherry-pick favourable studies, omit conflicting evidence, or cite industry-funded trials without flagging the conflict of interest where known.
The research is one thing, what to take, at what dose, paired with what, is another. We compose stacks that turn the evidence into a daily routine.
Studies referenced are real published research. Summaries are paraphrased for accessibility, for exact methods and full text, click through to PubMed. Educational use only, not medical advice. Consult a qualified clinician before starting any new supplement.