StackTerminal.Health

BETA

L-Theanine

Often paired with caffeine for 'calm focus'; evidence suggests reduced jitteriness & improved attention in some contexts.

focusstresscaffeine
Evidence last reviewed: 04 Apr 2026
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Trade-offs & context
Known concerns, timing considerations, & interactions
Timing

Mild drowsiness at high doses — pair with caffeine for balanced alertness or take alone in evenings

Context: doses >400mg

Dot colour: High concern  Moderate   Low / note
Biomarkers studied
Outcomes directly measured across the evidence records below
Cognitive
Cognitive FunctionFocus / AttentionReaction Time
Evidence
2 records
Attention & cognitive performance (combined with caffeine)
Healthy adultsRCT (double-blind, crossover)
PUBMEDModerate

L-theanine (100 mg) + caffeine (50 mg) improved attention-switching speed & accuracy vs. placebo at 60 min; L-theanine alone showed no significant cognitive effects.

Dose: 200 mgDuration: AcuteTiming: 60 min
Most consistent evidence is for the caffeine + theanine combination, not theanine alone.
Cognitive function (standalone L-theanine)
Healthy adults (5 RCTs, n=148)Systematic review & meta-analysis of RCTs
PUBMEDLow

L-theanine showed dose-dependent effects on rapid visual information processing & recognition reaction time; non-significant for simple reaction time & Stroop. Overall evidence promising but not conclusive.

Dose: 200 mgDuration: Acute to 4 weeks
Standalone effects are less consistent than combination with caffeine.
Forms
L-Theanine
Commonly 100–200 mg with caffeine.

Stacks containing L-Theanine

Public community stacks that include this ingredient.

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sleepwomens-health

Cycle-phase support focused on calm & sleep quality without stimulants.

Vitex agnus-castus
20mg
Glycine
3000mg
L-Theanine
200mg
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focus

Supports focus & mental clarity without stimulants.

L-Theanine
200mg
L-Tyrosine
1000mg
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recoverysleep

Designed to support sleep quality, parasympathetic activation, & overnight recovery without heavy sedation.

Magnesium Glycinate
400mg
Glycine
3000mg
L-Theanine
200mg
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longevityanti-agingcellular-health

Bryan Johnson's Blueprint Longevity Mix is the core daily powder from his self-quantified anti-aging protocol. It combines NAD+ pathway support (CaAKG), collagen precursors (Glycine, Lysine, Vitamin C), joint protection (Glucosamine, Sodium Hyaluronate), mitochondrial support (Creatine, CoQ10-adjacent), and antioxidant defence (Glutathione, Taurine). Every ingredient is dosed at clinically relevant levels validated through continuous biomarker tracking.

Creatine Monohydrate
2500mg
Calcium Alpha-Ketoglutarate (CaAKG)
2000mg
Taurine
1500mg
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stressmoodanxiety

Combining Holy Basil with L-Theanine can reduce stress and balance mood. Holy Basil is an adaptogen that helps manage stress, while L-Theanine promotes relaxation without sedation.

Holy Basil (Tulsi)
300mg
L-Theanine
100mg
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focus

Supports alertness with lower jitter risk than caffeine.

Theacrine
100mg
L-Theanine
200mg
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sleepfocus

Supports attention & cognitive resilience without stimulants.

L-Theanine
200mg
L-Tyrosine
1000mg
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