usage6 min readエビデンス確認日： 2026年9月28日

Nootropics for Focus vs. Memory: Which Ingredients Do What?

A use-case guide to choosing nootropic ingredients based on your specific cognitive goal — sustained attention, memory encoding, recall speed, or creative thinking.

Defining the goals

Cognitive enhancement is not monolithic — different tasks engage different brain systems. Focus (sustained attention) primarily involves the prefrontal cortex and dopaminergic/noradrenergic systems. Memory encoding (forming new memories) involves the hippocampus and the cholinergic system. Memory recall (retrieving stored memories quickly) involves different neural networks from encoding. Creative thinking engages default mode network activity. Each goal responds to different ingredients, which is why the best nootropic "stack" depends on what you are actually trying to improve.

Best for focus and sustained attention

L-Theanine (200mg) + Caffeine (100mg) is the gold standard for acute focus — 30–60 minutes to effect; controlled trials have measured its benefits within roughly the first 2 hours after dosing. L-Tyrosine is best for focus under stress, sleep deprivation, or multitasking — but the trials showing this used about 100–150mg per kg of body weight per dose (roughly 7–12g for a 70–100kg adult), 10–20 times more than a 500–1000mg dose, at which those effects would not be expected. Citicoline (250mg) supports sustained attention by maintaining acetylcholine availability during long cognitive sessions. Rhodiola Rosea (200mg) reduces mental fatigue for extended focus sessions. When comparing multi-ingredient stacks built around citicoline and L-tyrosine for focus, check each ingredient's dose against the trial figures above.

Best for memory encoding (learning new things)

Bacopa Monnieri (300mg, 55% bacosides) is the best-evidenced ingredient for improving the speed and durability of memory encoding — but requires 8–12 weeks. Alpha-GPC (300mg) provides an acute cholinergic boost that improves encoding during the dose window. Lion's Mane supports long-term neuroplasticity that underpins learning capacity; the main human trial showing a cognitive benefit (in mild cognitive impairment) used 3,000mg per day — six times a 500mg dose. Phosphatidylserine improves signal transduction speed across synapses. Positive single-ingredient trials mostly used 100–300mg per day (PMID 21103034, 20523044), while a review of the wider literature (PMID 25933483) cites 300–800mg per day; the benefit is most consistent in older adults. When comparing multi-ingredient stacks built around bacopa and lion's mane for memory, check each ingredient's dose against the trial figures above.

Best for recall speed

Recall speed — how quickly you can retrieve stored information — is influenced by acetylcholine availability, dopamine signalling, and synaptic transmission speed. Huperzine A (100mcg, cycled) produces the sharpest acute improvement in recall by preserving acetylcholine. Phosphatidylserine supports transmission speed. Rhodiola improves recall under conditions of stress or fatigue (when catecholamine depletion would otherwise slow retrieval). Note: none of these can retrieve information that was never well-encoded — improving encoding comes first.

Best for creative thinking and insight

Creative thinking correlates with increased default mode network activity and alpha brain wave amplitude. L-Theanine is the strongest nootropic intervention for alpha wave induction. Lion's Mane supports the neuroplasticity that underlies cognitive flexibility. Microdosed psychedelics (not discussed here — legal status varies) are sometimes promoted for creativity, but rigorous blinded trials have not replicated the anecdotal reports: a 2022 double-blind, placebo-controlled psilocybin microdosing study found no evidence of enhanced creativity or cognitive function and concluded that expectation explains at least some of the reported benefits. Adaptogens (Ashwagandha, Rhodiola) support creative cognition indirectly by reducing the performance anxiety and stress that suppresses creative output.

Nootropics in Japan

Products in Japan

Consumer Affairs Agency (FFC)

Prefecture guides

Regulatory note

本ページは教育目的の編集コンテンツであり、医学的助言を構成するものではありません。日本国内で販売される機能性表示食品（FFC）および特定保健用食品（FOSHU）は、消費者庁への届出または許可を必要とします。届出のない輸入品については、日本の薬機法（旧薬事法）の下で疾病治療を示唆する表現は規制されます。サプリメントを開始する前に、必ず資格のある医療専門家にご相談ください。This page is editorial and not medical advice. Foods with Function Claims (FFC) and Foods for Specified Health Uses (FOSHU) sold in Japan require notification or approval from the Consumer Affairs Agency. Imported products without notification cannot make disease-treatment claims under the Pharmaceuticals and Medical Devices (PMD) Act. Note: In July 2026, the Consumer Affairs Agency (CAA) opened a public comment period (Notice No. 235080088, closes 30 July 2026) on proposed revisions to permitted claim wording for FFC-notified ingredients including DHA, phosphatidylserine, and NMN; compliant claim language may require updating once the final Cabinet Office Order is published. Consult a qualified healthcare professional before starting any supplement.

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