cognitive · Outcome
Subjective mental sharpness and ability to sustain focus. Downstream of sleep, glucose stability, and neurotransmitter precursors.
How to measure: Daily 1-10 rating; n-back or PVT score if you want objective. Brain-fog episodes per week are a useful counter-metric.
Three levers, one stack. Each works through a different mechanism. They compound.
Mixed effect on memory & cognition
3-5 g daily · Any time; consistency matters more than timing
Evidence
Effect size
Research
11 papers
directional · 11 studies · mixed · no reliable magnitude
Why: The strongest cognitive supplement with consistent effects across multiple meta-analyses. Effect on well-rested users is small; under sleep deprivation or vegetarian diets, meaningful. Cheap, well-tolerated, saturates muscle and brain phosphocreatine over 2-4 weeks.
See the Creatine Monohydrate pageImproves memory & cognition
2-4 sessions/week · Any time; morning may stack with caffeine for cognition
Evidence
Effect size
Research
71 papers
directional · 71 studies · no reliable magnitude
Improves memory & cognition
Evidence
Effect size
Research
7 papers
directional · 7 studies · no reliable magnitude
Everything we found, ranked by how strongly we recommend it. Tap any to see the studies.
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Every pick has two signals. They answer different questions and we never bundle them into one number.
Effect size
How big is the change on cognitive clarity, in the units that matter for this outcome.
Confidence
How sure are we the effect is real for cognitive clarity, given the studies we have.
For every pick, the “papers” number is how many studies we've cataloged that test this entity for cognitive clarity. “Favorable” means the study reported the direction you want.
The tier badge (S, A, B…) on the entity itself is its overall research confidence across all outcomes. It's the same letter wherever you see this entity on the site, not specific to cognitive clarity.
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Why: The single most-studied cognitive intervention. BDNF rise from training drives neurogenesis and synaptic plasticity. Effects compound over weeks. Aerobic exercise has comparable evidence, pick whichever you'll actually do.