Performance on tasks that test selecting or switching attention. A task result does not measure general intelligence or subjective focus.
Measured endpoints are tied to a particular task, population, and exposure. A finding cannot be generalized to a different outcome without supporting evidence.
Accuracy improved on a specific switching task; this does not quantify a general cognitive boost. Source
Some task performance improved with the caffeine combination. The result does not isolate a standalone theanine benefit. Source
Attention-task performance improved in the subgroup meeting ADHD diagnostic criteria. Participants without that diagnosis showed a different response pattern. Source
Each relationship keeps its participants and their roles together. Source details explain what the connection supports.
27 healthy volunteers; acute crossover comparison with placebo.
Limitation A co-study does not establish long-term benefit or synergy.
Caffeine · Sourced draft27 healthy volunteers; acute crossover comparison with placebo.
Limitation This does not isolate theanine-alone benefit.
L-theanine · Sourced draftA small randomized study tested the combination. Co-study is not a recommendation to combine substances.
Tagged articles and participants in the relationships above. A shared tag alone does not establish a causal effect.
A familiar stimulant with an unusually rich evidence base. Its effects depend on timing, tolerance and how quickly your body clears it.
Sourced draftAmino acid derivativeA tea-derived amino acid studied alone and alongside caffeine. Small attention studies offer useful signals, with important limits.
Sourced draftStimulant medicineA stimulant medicine with formulation-dependent delivery. ADHD treatment findings and attention-task results should retain their population and exposure context.
Sourced draftSupporting reading for this original editorial definition. Independent editorial review has not been recorded.
Caffeine with L-theanine improved some attention-task outcomes in 27 healthy volunteers.
Limitation Small, short-term study; selected laboratory tasks do not establish everyday productivity or long-term benefit. Authors were affiliated with Unilever.
Funding / disclosures Funding not assessed; author affiliations include Unilever.
Source in CaffeineCaffeine with L-theanine improved some attention-task outcomes in 27 healthy volunteers.
Limitation Small, short-term study; selected laboratory tasks do not establish everyday productivity or long-term benefit. Authors were affiliated with Unilever.
Funding / disclosures Funding not assessed; author affiliations include Unilever.
Source in L-theanineObserved changes in sustained attention and spatial working memory in the diagnosed subgroup.
Limitation Small acute study, with differing diagnostic subgroups; not evidence for universal enhancement.
Funding / disclosures Not assessed in this draft.
Source in Methylphenidate