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ハーブ臨床用量 · 900mg–1.2g DHA/day (the dose range of the positive trials)効果発現時間 · About 24 weeks — both positive cognitive RCTs ran 6 months

DHA (Omega-3)

DHA is essential for brain development and maintenance, but RCT results are mixed. A 2012 Cochrane review (n=4,080) found no cognitive benefit of omega-3 supplements in cognitively healthy older adults, and a 2025 meta-analysis found no meaningful ADAS-Cog benefit once Alzheimer's has developed. Two 6-month RCTs were positive: 900mg DHA/day improved learning and recognition memory in age-related cognitive decline (Yurko-Mauro et al., 2010 — sponsored by the algal-DHA maker Martek, with a Martek employee as lead author), and 1.16g/day improved memory and working-memory reaction times in healthy adults aged 18–45 with low DHA intake (Stonehouse 2013). A 2021 NIH-funded meta-analysis (n=81,210) found omega-3 supplements raise atrial fibrillation risk, more so above 1g/day.

By The Nootropic Lab editorial teamUpdated 8 min read✓ Fact-checked

エビデンス確認日:

作用機序

Docosahexaenoic acid (DHA) is the primary structural omega-3 fatty acid in the brain, constituting ~40% of polyunsaturated fatty acids in neuronal membranes. DHA maintains membrane fluidity, enabling proper receptor function, ion channel activity, and synaptic vesicle dynamics. It also resolves neuroinflammation via specialised pro-resolving mediators (SPMs) and supports BDNF (brain-derived neurotrophic factor) expression for neuroplasticity.

臨床エビデンスの概要

DHA is essential for brain development and maintenance, but RCT results are mixed. A 2012 Cochrane review (n=4,080) found no cognitive benefit of omega-3 supplements in cognitively healthy older adults, and a 2025 meta-analysis found no meaningful ADAS-Cog benefit once Alzheimer's has developed. Two 6-month RCTs were positive: 900mg DHA/day improved learning and recognition memory in age-related cognitive decline (Yurko-Mauro et al., 2010 — sponsored by the algal-DHA maker Martek, with a Martek employee as lead author), and 1.16g/day improved memory and working-memory reaction times in healthy adults aged 18–45 with low DHA intake (Stonehouse 2013). A 2021 NIH-funded meta-analysis (n=81,210) found omega-3 supplements raise atrial fibrillation risk, more so above 1g/day.

ヒト効果マトリクス

Based on human clinical trials only. Animal and in-vitro data excluded.

効果エビデンス効果の大きさ研究数
Memory (Age-Related Decline) moderate
中
1
Memory (Healthy Adults) moderate
中
1
Mood & Depression moderate
小
—
Brain Structure Preservation moderate
中
—

Evidence key: Strong = multiple consistent RCTs · Moderate = smaller/fewer RCTs · Preliminary = early trials or small n · Mixed = conflicting results

実証された効果

  • Learning and recognition memory in age-related cognitive decline (900mg/day)
  • Memory and reaction time in healthy adults with low DHA intake (1.16g/day)
  • Neuronal membrane integrity

副作用と注意事項

  • Atrial fibrillation: a 2021 meta-analysis of cardiovascular RCTs (PMID 34612056, n=81,210) found omega-3 supplements raised atrial fibrillation risk (HR 1.25), rising to HR 1.49 at more than 1g/day — talk to your doctor if you have heart-rhythm problems
  • Fishy aftertaste or burps
  • Mild GI problems (under 15% of participants in the Cochrane review, similar to placebo)
  • Potential blood-thinning effect at very high doses (>3g/day)

摂取方法

Dosage900mg–1.2g DHA/day. If combining with EPA, note the atrial fibrillation risk rose above 1g/day of total omega-3 in cardiovascular trials
TimingWith a meal containing fat for optimal absorption. Can be taken any time of day.
With foodEssential — DHA is fat-soluble, so take it with a fat-containing meal.
FormsFish oil, krill oil, or algal oil (vegan). Algal DHA avoids heavy metal concerns; no head-to-head trial has compared algal and fish DHA on cognitive outcomes.

スタッキングの推奨

DHA (Omega-3)と相性の良い成分とその理由。

Phosphatidylserine

DHA provides the structural fat for membranes; PS is the phospholipid that organises membrane architecture. Together they provide comprehensive neuronal membrane support.

Lion's Mane

DHA maintains membrane integrity while Lion's Mane stimulates NGF for neuroplasticity. Foundational + growth-oriented brain support.

Citicoline

Citicoline provides choline for membrane phospholipid synthesis; DHA provides the fatty acid substrate. Together they supply the raw materials for brain cell membrane repair.

よくある質問

DHA vs EPA — which matters more for brain health?

DHA is the structural omega-3 in brain membranes (~40% of brain PUFA), making it more directly relevant to cognitive function. EPA is more potent as an anti-inflammatory and shows stronger effects for mood/depression. For brain health, prioritise DHA — the positive cognitive trials used 900mg–1.16g DHA per day. For mood support, prioritise EPA. Most quality supplements provide both; keep the atrial fibrillation signal above 1g/day of total omega-3 in mind.

Can I get enough DHA from diet alone?

If you eat fatty fish (salmon, mackerel, sardines) 2-3 times per week, you likely get sufficient DHA. Most people in Western diets consume far below optimal levels. Vegetarians and vegans are particularly at risk for deficiency — algal DHA supplements are the solution. A blood test (Omega-3 Index) can measure your actual status.

Is fish oil or algal oil better?

DHA is the same molecule from either source. Algal oil avoids mercury/heavy metal concerns and is suitable for vegetarians. Fish oil provides a natural DHA+EPA ratio. No head-to-head trial has compared them on cognitive outcomes — choose based on dietary preference and quality of the specific product.

How long before I notice cognitive effects?

DHA works by rebuilding membrane composition, which is a slow process. Both positive cognitive RCTs ran for 24 weeks (6 months). You will not feel an acute effect like caffeine or L-theanine. Think of DHA as a long-term infrastructure investment, not a performance supplement.

Top stacks containing DHA (Omega-3)

FANCL BRAINs

7.2/10

FANCL

Suntory DHA & EPA + Sesamin EX

7.1/10

Suntory

DHA (Omega-3) 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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