Place · Level 3 · Supplement
α-GPC + CDP-Choline (Citicoline)
胆碱衍生形态 · ACh 前体 · 卒中后认知部分证据 · 健康人证据弱 · ⚠️ 长期 α-GPC > 3 年中风风险信号 (Tasca 2021 韩国全国 N=12k, HR 1.4-1.8)
Story path
Chapter 1
Two choline derivatives
Two choline derivatives
α-GPC (alpha-glycerylphosphorylcholine) plus CDP-choline (citicoline, cytidine 5′-diphosphocholine) are two choline-derived nootropic supplements that complement the atlas choline story.
Recap (from the atlas choline story):
Choline: essential nutrient (AI men 550 / women 425 mg/day)Functions: phosphatidylcholine synthesis + acetylcholine (ACh) neurotransmitter + one-carbon metabolism (BHMT pathway) + hepatic lipid transport
α-GPC:
Chemistry: glycerylphosphocholine, naturally present in breast milk and brainHigh brain bioavailability (crosses the blood–brain barrier: The 'security gate' on brain vessels that blocks most substances in blood from entering the brain. well)Content: 40% choline + glycerophosphate + partial direct acetylcholine precursorA prescription drug in some European countries for dementia / post-stroke cognitionSold OTC as a nootropic in the US / China
CDP-choline (Citicoline):
Chemistry: cytidine diphosphate choline, an intermediate in adenosine triphosphate: The cell's universal energy currency — almost everything that costs energy spends it. / phospholipid synthesisGood brain bioavailabilityContent: 18% choline + 32% cytidine + phosphatePrescription drug in Japan / Europe: Somazina, etc.OTC: 'Cognizin' (a commercial high-purity form used in most cognitive RCTs)
Differences from plain choline (Choline bitartrate / Phosphatidylcholine):
Plain choline: whole-body supplementation (liver / heart / brain all use it), best cost-effectivenessα-GPC / CDP: more brain-targeted, but expensivePhosphatidylcholine (PC, lecithin): also good bioavailability, but more of a membrane component than a nootropic pathwayTMAO risk: high-dose choline (any form) is processed by gut bacteria into TMA, oxidized in the liver to TMAO; some studies link this to cardiovascular risk (covered in the atlas choline + TMG story), with large individual variation
Why atlas covers this section:
The nootropic market is growing fast, and α-GPC + CDP are mainstream single productsClinical evidence is mixed: B-tier for post-stroke cognition and dementia; weak for healthy-person nootropic effectsHeavy marketing around 'memory / focus / brain protection' — atlas goes through the evidence claim by claimNew warning: Tasca 2021 neurology retrospective data suggests long-term α-GPC supplementation (3+ years) may be associated with stroke risk; replication is ongoing, but it can't be ignored
Recap (from the atlas choline story):
Choline: essential nutrient (AI men 550 / women 425 mg/day)Functions: phosphatidylcholine synthesis + acetylcholine (ACh) neurotransmitter + one-carbon metabolism (BHMT pathway) + hepatic lipid transport
α-GPC:
Chemistry: glycerylphosphocholine, naturally present in breast milk and brainHigh brain bioavailability (crosses the blood–brain barrier: The 'security gate' on brain vessels that blocks most substances in blood from entering the brain. well)Content: 40% choline + glycerophosphate + partial direct acetylcholine precursorA prescription drug in some European countries for dementia / post-stroke cognitionSold OTC as a nootropic in the US / China
CDP-choline (Citicoline):
Chemistry: cytidine diphosphate choline, an intermediate in adenosine triphosphate: The cell's universal energy currency — almost everything that costs energy spends it. / phospholipid synthesisGood brain bioavailabilityContent: 18% choline + 32% cytidine + phosphatePrescription drug in Japan / Europe: Somazina, etc.OTC: 'Cognizin' (a commercial high-purity form used in most cognitive RCTs)
Differences from plain choline (Choline bitartrate / Phosphatidylcholine):
Plain choline: whole-body supplementation (liver / heart / brain all use it), best cost-effectivenessα-GPC / CDP: more brain-targeted, but expensivePhosphatidylcholine (PC, lecithin): also good bioavailability, but more of a membrane component than a nootropic pathwayTMAO risk: high-dose choline (any form) is processed by gut bacteria into TMA, oxidized in the liver to TMAO; some studies link this to cardiovascular risk (covered in the atlas choline + TMG story), with large individual variation
Why atlas covers this section:
The nootropic market is growing fast, and α-GPC + CDP are mainstream single productsClinical evidence is mixed: B-tier for post-stroke cognition and dementia; weak for healthy-person nootropic effectsHeavy marketing around 'memory / focus / brain protection' — atlas goes through the evidence claim by claimNew warning: Tasca 2021 neurology retrospective data suggests long-term α-GPC supplementation (3+ years) may be associated with stroke risk; replication is ongoing, but it can't be ignored
Chapter 2
Clinical evidence by indication
Clinical evidence by indication
Evidence tiering by indication:
1. Acute ischemic stroke (citicoline)
ICTUS Trial (Dávalos 2012 Lancet, N = 2,298): citicoline 2000 mg/day × 6 weeks did not show functional improvement vs placeboEarly small trials were positive; this large RCT was negativeSubgroup analyses showed signal in some mild patients / elderly women2024 clinical positioning: not recommended for acute stroke, but some hospitals still use it for chronic recovery
2. Vascular cognitive impairment / dementia
IDEALE 2013 + COBRA 2015 and other RCTs: moderately positiveCiticoline has B-tier evidence in vascular cognitive impairmentCiticoline + antiplatelet drug combination: some studies show synergy
3. Alzheimer's disease (AD)
α-GPC + donepezil: some positive studies (Amenta 2014)Solo evidence is weakDoesn't replace standard AChE inhibitors
4. Traumatic brain injury (TBI)
COBRIT Trial (Zafonte 2012 JAMA, N = 1,213): citicoline × 90 days was negative (no functional improvement)Early small trials were positive; large RCT was negative
5. Healthy-person nootropic (attention / memory / anxiety)
Most are small trials (N < 100) with mixed resultsConant 2024 review: some trials show moderate effect, but heterogeneity is large and funding mostly comes from the supplement industryB-C tier evidence
6. Exercise performance (α-GPC)
Bellar 2015 + Marcus 2017: a single 600 mg α-GPC dose briefly raises strength training power by 5–15%Mechanism: raises ACh, improves neuromuscular conductionB-tier evidence (exercise performance)
Important warning: Tasca 2021 long-term α-GPC and stroke signal
Korean nationwide retrospective study (N = 12,000+)Long-term α-GPC use (3+ years) is associated with elevated stroke risk (HR 1.4–1.8)Hypothesized mechanisms: TMAO / hyperhomocysteinemia / plateletsReplication and causality aren't yet established, but the elderly and cardiovascular high-risk patients should be cautious2024 consensus: long-term preventive use is not recommended
Connections to other atlas pathways:
TMAO risk (covered in choline / TMG): α-GPC and CDP also route through gut bacteria into TMA → TMAOVLDL / hepatic lipids: plain choline works mainly in the liver; α-GPC / CDP skew toward the brainMethylation (one-carbon metabolism): choline → TMG → BHMT alternate path (atlas TMG L4)
1. Acute ischemic stroke (citicoline)
ICTUS Trial (Dávalos 2012 Lancet, N = 2,298): citicoline 2000 mg/day × 6 weeks did not show functional improvement vs placeboEarly small trials were positive; this large RCT was negativeSubgroup analyses showed signal in some mild patients / elderly women2024 clinical positioning: not recommended for acute stroke, but some hospitals still use it for chronic recovery
2. Vascular cognitive impairment / dementia
IDEALE 2013 + COBRA 2015 and other RCTs: moderately positiveCiticoline has B-tier evidence in vascular cognitive impairmentCiticoline + antiplatelet drug combination: some studies show synergy
3. Alzheimer's disease (AD)
α-GPC + donepezil: some positive studies (Amenta 2014)Solo evidence is weakDoesn't replace standard AChE inhibitors
4. Traumatic brain injury (TBI)
COBRIT Trial (Zafonte 2012 JAMA, N = 1,213): citicoline × 90 days was negative (no functional improvement)Early small trials were positive; large RCT was negative
5. Healthy-person nootropic (attention / memory / anxiety)
Most are small trials (N < 100) with mixed resultsConant 2024 review: some trials show moderate effect, but heterogeneity is large and funding mostly comes from the supplement industryB-C tier evidence
6. Exercise performance (α-GPC)
Bellar 2015 + Marcus 2017: a single 600 mg α-GPC dose briefly raises strength training power by 5–15%Mechanism: raises ACh, improves neuromuscular conductionB-tier evidence (exercise performance)
Important warning: Tasca 2021 long-term α-GPC and stroke signal
Korean nationwide retrospective study (N = 12,000+)Long-term α-GPC use (3+ years) is associated with elevated stroke risk (HR 1.4–1.8)Hypothesized mechanisms: TMAO / hyperhomocysteinemia / plateletsReplication and causality aren't yet established, but the elderly and cardiovascular high-risk patients should be cautious2024 consensus: long-term preventive use is not recommended
Connections to other atlas pathways:
TMAO risk (covered in choline / TMG): α-GPC and CDP also route through gut bacteria into TMA → TMAOVLDL / hepatic lipids: plain choline works mainly in the liver; α-GPC / CDP skew toward the brainMethylation (one-carbon metabolism): choline → TMG → BHMT alternate path (atlas TMG L4)
Chapter 3
Form comparison
Form comparison
Comparing six choline forms:
Purity and quality:
Cognizin (CDP-choline commercial brand, Kyowa Hakko, Japan): used in most RCTs, purity assuredAlphaSize (α-GPC commercial brand, Chemi Nutra, US): soy-derived, used in some RCTsThird-party certification (USP / NSF / Informed-Choice) is the quality floor
Dosing:
CDP-choline: 250–500 mg × 2/day (nootropic); 2000 mg/day (stroke)α-GPC: 300–600 mg/day (nootropic); 1200 mg/day (dementia, divided doses)Exercise performance: α-GPC 600 mg 30–60 minutes pre-trainingFood (eggs + organ meats + fish): plain choline is sufficient; no need for α-GPC / CDP
Time to effect:
Exercise performance (α-GPC): single dose, effect within 30–60 minutesCognitive nootropic: subjective feeling at 1–4 weeks, objective testing at 4–12 weeksPost-stroke cognition: assess at 3–6 months
Stacking with other nootropics:
Caffeine + L-theanine: synergy (covered in the atlas caffeine-l-theanine story)Bacopa monnieri: Ayurvedic, B-tier memory evidenceLion's mane: neurotrophic factor hypothesis, debunked in Batch VIModafinil / Adderall: prescription drugs, not supplements; stacking with supplements is high-risk
Safety:
Common side effects: nausea / headache / insomnia / tachycardia (at high dose)TMAO association: long-term high doses are worth watchingWorsened depression: α-GPC raises anxiety / irritability in some peoplePregnancy / lactation: data lacking (food choline is safe; skip supplements)Children: not recommended (except for clear medical indication)
Contraindications / warnings:
Bipolar depression: α-GPC / CDP may trigger or worsen mania (caution)On SSRI / anticholinergic drugs: interaction riskHigh cardiovascular risk: long-term — watch the Tasca 2021 signalStop 1 week before surgery: bleeding risk
'Focus miracle drug' marketing compared point by point:
'1 week of taking it gives a huge brain boost' marketing is mostly placebo effectReal effect is mild with large individual variationThe real levers for focus are sleep, exercise, nutrition, less screen time, less stress — no supplement can compete
| Form | Choline % | BBB | Price | Main use |
|---|---|---|---|---|
| Choline bitartrate | 41% | Medium | $ | Whole-body supplementation when food is insufficient |
| Phosphatidylcholine (PC, lecithin) | 13% | Medium | $$ | Membrane health / liver / gut |
| CDP-choline (citicoline) | 18% | High | $$$ | Post-stroke cognition / nootropic |
| α-GPC | 40% | High | $$$ | Dementia adjunct / exercise performance / nootropic |
| N-acetylcysteine (NAC) | N/A | High | $ | Not a choline form, but often stacked with choline |
| DMAE | N/A | High | $$ | Old nootropic, weak evidence |
Purity and quality:
Cognizin (CDP-choline commercial brand, Kyowa Hakko, Japan): used in most RCTs, purity assuredAlphaSize (α-GPC commercial brand, Chemi Nutra, US): soy-derived, used in some RCTsThird-party certification (USP / NSF / Informed-Choice) is the quality floor
Dosing:
CDP-choline: 250–500 mg × 2/day (nootropic); 2000 mg/day (stroke)α-GPC: 300–600 mg/day (nootropic); 1200 mg/day (dementia, divided doses)Exercise performance: α-GPC 600 mg 30–60 minutes pre-trainingFood (eggs + organ meats + fish): plain choline is sufficient; no need for α-GPC / CDP
Time to effect:
Exercise performance (α-GPC): single dose, effect within 30–60 minutesCognitive nootropic: subjective feeling at 1–4 weeks, objective testing at 4–12 weeksPost-stroke cognition: assess at 3–6 months
Stacking with other nootropics:
Caffeine + L-theanine: synergy (covered in the atlas caffeine-l-theanine story)Bacopa monnieri: Ayurvedic, B-tier memory evidenceLion's mane: neurotrophic factor hypothesis, debunked in Batch VIModafinil / Adderall: prescription drugs, not supplements; stacking with supplements is high-risk
Safety:
Common side effects: nausea / headache / insomnia / tachycardia (at high dose)TMAO association: long-term high doses are worth watchingWorsened depression: α-GPC raises anxiety / irritability in some peoplePregnancy / lactation: data lacking (food choline is safe; skip supplements)Children: not recommended (except for clear medical indication)
Contraindications / warnings:
Bipolar depression: α-GPC / CDP may trigger or worsen mania (caution)On SSRI / anticholinergic drugs: interaction riskHigh cardiovascular risk: long-term — watch the Tasca 2021 signalStop 1 week before surgery: bleeding risk
'Focus miracle drug' marketing compared point by point:
'1 week of taking it gives a huge brain boost' marketing is mostly placebo effectReal effect is mild with large individual variationThe real levers for focus are sleep, exercise, nutrition, less screen time, less stress — no supplement can compete
Chapter 4
Decision tree
Decision tree
α-GPC / CDP-choline decision path:
Q1: what's your goal?
A. Acute stroke (emergency phase):
Not recommended (ICTUS / COBRIT large RCTs negative)Standard stroke treatment (thrombolysis / thrombectomy + antiplatelet + secondary prevention) takes priority
B. Chronic post-stroke recovery / vascular cognitive impairment:
CDP-choline 500–1000 mg/day can be discussed with a neurologistB-tier evidence, assess at 6 months
C. Alzheimer adjunct (alongside an AChE inhibitor):
α-GPC 600–1200 mg/day can be discussed with a neurologistDoesn't replace donepezil / memantine
D. Healthy-person nootropic (focus / memory):
Minimal benefitTry 4–8 weeks looking at subjective + objective improvement; stop if no changeCDP-choline 250 mg × 2/day or α-GPC 300 mg/dayCost-effectiveness: compared with caffeine + L-theanine + sleep + exercise, the latter wins
E. Exercise performance (strength training):
α-GPC 600 mg pre-trainingB-tier evidence, can tryDon't take high doses every day long-term (Tasca 2021 warning)
Q2: can you replace it with food / plain choline?
With adequate egg yolks + organ meats + fish, most people have enough choline1–2 g/day choline from food + 1–2 g plain choline bitartrate as a boostReserve the brain-targeted forms (α-GPC / CDP) for special indications
Q3: warnings + contraindications:
High cardiovascular risk + long-term use: Tasca 2021 stroke signal — use cautionBipolar depression / anxiety: worsens in some peoplePregnancy / lactation / children: skipOn SSRI / anticholinergic drugs: discuss with physicianTMAO concern + cardiovascular disease: monitor
Q4: cost-effectiveness + realistic expectations:
¥100–300/month (α-GPC or CDP, mid-tier brand)vs prescription nootropics (modafinil etc.): prescription drugs are stronger but carry dependence + side effectsvs lifestyle: sleep + exercise + nutrition are stronger nootropics
The most-overlooked nootropic levers (atlas position):
1. Sleep 7–9 hours — the single strongest
2. Exercise — BDNF + cerebral blood flow
3. Limit screen time + reduce social media — attention training
4. Diet (low UPF + Mediterranean) — chronic inflammation ↓
5. Mindfulness / meditation — attention + working memory
6. Limit alcohol
7. Manage stress — chronic stress damages the brain
8. Learning new skills / social engagement — neuroplasticity
These levers are zero-cost and zero-side-effect, with combined effect far exceeding any nootropic supplement.
Closing the loop with other atlas stories:
choline + tmg-betaine L3 + L4 (upstream choline metabolism)caffeine-l-theanine (synergistic nootropic)vitamin-b12/methylation + folate/one-carbon L4nervous/neurotransmitters L4 (ACh + the synapse big picture)depression-anxiety + sleep-apnea + insomnia (brain health foundations)
Atlas position: α-GPC and CDP are the two largest choline-derived molecules in the nootropic market. The real indications (post-stroke cognition / dementia adjunct / exercise performance) have B-tier evidence; the healthy-person nootropic case is weak, and long-term use carries a cardiovascular warning. Atlas doesn't sell panic and doesn't sell perfection — it lays the information out and lets the reader decide.
Q1: what's your goal?
A. Acute stroke (emergency phase):
Not recommended (ICTUS / COBRIT large RCTs negative)Standard stroke treatment (thrombolysis / thrombectomy + antiplatelet + secondary prevention) takes priority
B. Chronic post-stroke recovery / vascular cognitive impairment:
CDP-choline 500–1000 mg/day can be discussed with a neurologistB-tier evidence, assess at 6 months
C. Alzheimer adjunct (alongside an AChE inhibitor):
α-GPC 600–1200 mg/day can be discussed with a neurologistDoesn't replace donepezil / memantine
D. Healthy-person nootropic (focus / memory):
Minimal benefitTry 4–8 weeks looking at subjective + objective improvement; stop if no changeCDP-choline 250 mg × 2/day or α-GPC 300 mg/dayCost-effectiveness: compared with caffeine + L-theanine + sleep + exercise, the latter wins
E. Exercise performance (strength training):
α-GPC 600 mg pre-trainingB-tier evidence, can tryDon't take high doses every day long-term (Tasca 2021 warning)
Q2: can you replace it with food / plain choline?
With adequate egg yolks + organ meats + fish, most people have enough choline1–2 g/day choline from food + 1–2 g plain choline bitartrate as a boostReserve the brain-targeted forms (α-GPC / CDP) for special indications
Q3: warnings + contraindications:
High cardiovascular risk + long-term use: Tasca 2021 stroke signal — use cautionBipolar depression / anxiety: worsens in some peoplePregnancy / lactation / children: skipOn SSRI / anticholinergic drugs: discuss with physicianTMAO concern + cardiovascular disease: monitor
Q4: cost-effectiveness + realistic expectations:
¥100–300/month (α-GPC or CDP, mid-tier brand)vs prescription nootropics (modafinil etc.): prescription drugs are stronger but carry dependence + side effectsvs lifestyle: sleep + exercise + nutrition are stronger nootropics
The most-overlooked nootropic levers (atlas position):
1. Sleep 7–9 hours — the single strongest
2. Exercise — BDNF + cerebral blood flow
3. Limit screen time + reduce social media — attention training
4. Diet (low UPF + Mediterranean) — chronic inflammation ↓
5. Mindfulness / meditation — attention + working memory
6. Limit alcohol
7. Manage stress — chronic stress damages the brain
8. Learning new skills / social engagement — neuroplasticity
These levers are zero-cost and zero-side-effect, with combined effect far exceeding any nootropic supplement.
Closing the loop with other atlas stories:
choline + tmg-betaine L3 + L4 (upstream choline metabolism)caffeine-l-theanine (synergistic nootropic)vitamin-b12/methylation + folate/one-carbon L4nervous/neurotransmitters L4 (ACh + the synapse big picture)depression-anxiety + sleep-apnea + insomnia (brain health foundations)
Atlas position: α-GPC and CDP are the two largest choline-derived molecules in the nootropic market. The real indications (post-stroke cognition / dementia adjunct / exercise performance) have B-tier evidence; the healthy-person nootropic case is weak, and long-term use carries a cardiovascular warning. Atlas doesn't sell panic and doesn't sell perfection — it lays the information out and lets the reader decide.
Nootropic landscape · A + B tier (real evidence)
The nootropic (brain enhancer) industry was ~$5B globally in 2024, most of which is over-marketed supplements. Atlas gives a real evidence tiering:A-tier (strong evidence, genuinely useful):
Caffeine 50–200 mg: focus + reaction time + alertness; the single strongest evidence (atlas caffeine-l-theanine)L-theanine 100–200 mg + caffeine: synergy (reduces coffee anxiety + boosts focus)Adequate sleep 7–9 hours: the single strongest nootropic, no supplement can replace itExercise (30 min moderate aerobic): BDNF + cerebral blood flow + neuroplasticityMeditation / mindfulness: working memory + attention (Tang 2015 meta)
B-tier (moderate evidence, benefits some people):
Citicoline (CDP-choline) 500–1000 mg: post-stroke cognition + dementia adjunct (covered above)Bacopa monnieri 300 mg: memory consolidation (Kongkeaw 2014 meta), AyurvedicLion's mane (Hericium erinaceus) 1–3 g: neurotrophic factor induction, mild cognitive signal (Mori 2009)Rhodiola rosea 200–400 mg: reduces fatigue + performance under stress (Panossian 2010, atlas adaptogens)Ashwagandha 300–600 mg: stress + anxiety + sleep (Chandrasekhar 2012)Glycine 3 g at bedtime: subjective sleep improvement → indirect nootropicomega-3 EPA + DHA: long-term cognitive protection signal (not acute)
C + D tier + focus ranking + atlas stance
C-tier (weak evidence / mostly commercial):α-GPC: weak healthy-person evidence + long-term CV warning (Tasca 2021)Piracetam / Aniracetam / Oxiracetam: old nootropics, prescription in Europe / China, weak clinical benefitModafinil: prescription drug, REM sleep deprivation / narcolepsy; off-label use is popular but with real dependence + cardiovascular riskPhenibut: GABA analog, real addiction + withdrawal, atlas refuses to recommendDMAE: old nootropic, weak evidencePRL-8-53: a single 1978 trial, never replicated
D-tier / marketing (not recommended):
'Brain gold': mostly omega-3 + gimmick packaging'Multinutrient / Sinala' multi-ingredient products: weak signal'Lumosity / brain games': fined $2M by the FTC in 2016, no evidence for 'brain improvement''NMN / NR': anti-aging marketing, cognitive benefit RCT negative (covered in atlas nmn-nr section)
'Focus / attention' ranking (by real effect):
1. Sleep + exercise + limit social media + meditation ← zero-cost + zero side effects + strong effect
2. Caffeine + L-theanine ← cheap + immediate effect
3. Environment: silence + single-task + reduce notifications
4. Diet: Mediterranean / low UPF + adequate protein
5. (Optional trial) B-tier nootropic: Bacopa / Rhodiola / Citicoline
6. (Clinical indication) prescription drug: after ADHD diagnosis
Atlas position: 'find a supplement that makes me focus' is itself the wrong question. Attention, memory, and thinking capacity are outputs of overall brain health, not products of a single neurotransmitter. Getting the four foundations of sleep, exercise, nutrition, and mental health to 80% returns far more than any nootropic.
On 'cognitive decline worries + wanting a nootropic for anti-aging':
The levers that genuinely prevent cognitive decline: BP control, glucose control, quitting smoking, exercise, education, social engagement, hearing aids, reduced alcohol, treating depressionLivingston 2024 Lancet: combining 14 lifestyle factors can cut dementia risk by 45%No nootropic supplement comes close to this number