Focus & Cognition
Caffeine + L-Theanine
L-theanine smooths caffeine's alertness without blunting it — the most-studied cognitive combination in supplement research.
Performance
Most widely used performance enhancer. Improves endurance, strength, and cognitive function through adenosine antagonism.
Full Caffeine profile →Amino Acid
Calming amino acid from tea that promotes relaxation without sedation. Synergistic with caffeine for focused calm.
Full L-Theanine profile →Why they work together
Caffeine blocks adenosine receptors to produce alertness, but also stimulates sympathetic output — hence jitters, elevated heart rate, and anxiety at higher doses. L-theanine is an amino acid that raises alpha-wave activity and blunts sympathetic arousal without causing drowsiness. Combined, you get caffeine's alertness and focus benefits with substantially reduced anxiety side effects. Multiple EEG studies show enhanced attention-task performance with the combination beyond what either produces alone.
How to dose them
100 mg caffeine + 200 mg L-theanine (the canonical 2:1 ratio), taken 30 minutes before the task that needs focus. Morning or pre-task only — caffeine's 6-hour half-life means evening dosing disrupts sleep even paired with L-theanine.
Evidence
Multiple RCTs show improved attention, accuracy on cognitive tasks, and reduced subjective anxiety compared to caffeine alone. The combination is in most serious pre-workout and nootropic formulas.
Watch-outs
Standard caffeine interactions apply — medications metabolized by CYP1A2, pregnancy, and cardiac conditions are all reasons to discuss with a clinician. L-theanine itself has no known drug interactions at supplement doses. Caffeine tolerance builds with daily use — cycling 2 weeks on / 1 week off preserves effectiveness.
Next steps
Educational only. Synergy pairs are not prescriptions. Run any new supplement combination past your clinician if you take prescription medication.