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L-Theanine

Amino Acidoral · inferred

Amino acid found in tea leaves. Promotes calm focus by increasing alpha brain waves. Often paired with caffeine.

Projected serum levels — 200 mg, once daily

L-Theanine
L-Theanine modeled serum levels, 200 mg once daily over 15 days Population-based pharmacokinetic estimate. Steady state reached after approximately 1 days. 0 50 100 150 200 Day 0 Day 4 Day 8 Day 11 Day 15 Time on a regular schedule ≈ steady state · day 1

Maintenance schedule: 200 mg once daily (oral).

Modeled steady state after ~1 days: peak ≈ 135 mg, trough ≈ 0.63 mg body load. Population-based estimate over 15 days for a 200 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.

Key facts

Category
Amino Acid
Route modeled
Oral
Model confidence
inferred
Half-life
1.2 h
Common dose
200 mg
Suggested maximum
800 mg/day
Reference dose range
100–800 mg (single dose)
Suggested cadence
once daily
Validated against
200 mg oral — Cmax 2.3 mg/L at 0.80 h

Documented interactions

  • moderate
    Ethanol (Alcohol) + L-Theanine Stacked effects

    Ethanol (Alcohol) and L-Theanine both push the gaba a and nmda in the same direction.

  • moderate
    Methaqualone (Quaalude / Mandrax) + L-Theanine Stacked effects

    L-Theanine and Methaqualone (Quaalude / Mandrax) both push the gaba a and nmda in the same direction.

  • moderate
    Nitrous Oxide + L-Theanine Stacked effects

    L-Theanine and Nitrous Oxide both push the gaba a and nmda in the same direction.

  • moderate
    St. John's Wort (Hypericum perforatum) + L-Theanine Stacked effects

    L-Theanine and St. John's Wort (Hypericum perforatum) both push the gaba a and nmda in the same direction.

  • moderate
    Taurine + L-Theanine Stacked effects

    L-Theanine and Taurine both push the endogenous amino acid pool and gaba a in the same direction.

  • watch
    3-MeO-PCP (3-Methoxyphencyclidine) + L-Theanine Stacked effects

    3-MeO-PCP (3-Methoxyphencyclidine) and L-Theanine both push the nmda in the same direction.

Serum checks 50 modeled interaction pairings for l-theanine across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.

Research behind this entry

  1. The combined effects of L-theanine and caffeine on cognitive performance and mood Owen GN et al. · Nutritional Neuroscience, 2008 DOI

    Study showed the combination of L-theanine (97 mg) and caffeine (40 mg) improved accuracy during task-switching and reduced susceptibility to distraction.

  2. Effects of L-theanine on attention and reaction time response Foxe JJ et al. · Journal of Functional Foods, 2012 DOI

    Study found L-theanine (100 mg) improved sustained attention and inhibitory control during a demanding cognitive task, particularly in high-anxiety-prone individuals.

  3. l-Theanine reduces psychological and physiological stress responses Kimura K et al. · Biological Psychology, 2007 DOI

    In a double-blind, counterbalanced laboratory experiment, 12 participants completed four acute mental-arithmetic stress sessions with L-theanine, placebo, or no treatment. L-theanine attenuated selected subjective and…

3 published studies referenced in the app, each with a plain-language summary.