The evidence suggests that L-theanine can improve cognitive performance, particularly when combined with caffeine. However, the effects of standalone L-theanine are less pronounced, and more research is needed to fully understand its benefits.
Attention & cognitive performance (combined with caffeine)Healthy adults · RCT (double-blind, crossover)Moderate
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.
Cognitive function (standalone L-theanine)Healthy adults (5 RCTs, n=148) · Systematic review & meta-analysis of RCTsLow
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.
PMS Calmer (Low-Stim, Cycle-Friendly)
Cycle-phase support focused on calm & sleep quality without stimulants.
Clean Stimulant Focus Stack
Supports alertness with lower jitter risk than caffeine.
Longevity Mix (Bryan Johnson)
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.
Stress Reduction and Mood Balance
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.
Focus Stack (No Stimulants)
Supports focus & mental clarity without stimulants.
Non-Stimulant Focus Stack
Supports attention & cognitive resilience without stimulants.
Sleep & Recovery Stack
Designed to support sleep quality, parasympathetic activation, & overnight recovery without heavy sedation.
Forms & usage▾
Take 100-200 mg of L-theanine, ideally with caffeine for daytime use or alone in the evening.
Safety & trade-offs1▾
Mild drowsiness at high doses — pair with caffeine for balanced alertness or take alone in evenings
Context: doses >400mg
●High ●Moderate ● Low / note