Alpha-GPC
Also sold as: Choline alphoscerate · L-alpha-glycerylphosphorylcholine · Glycerophosphocholine
A choline-containing compound studied in cognitive disorders and marketed as a nootropic or pre-workout ingredient. Clinical cognitive-disease findings do not establish a broad healthy-adult performance benefit.
Focus
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Research
- Focus: A small acute healthy-male RCT improved selected Stroop measures but not Flanker or N-back. Dementia and MCI treatment evidence is a separate clinical context.
REALITY CHECK // Cognitive-disease studies suggest benefits, including in combinations with donepezil, but a nimodipine combination trial was negative. Healthy-adult evidence is narrow and physical-performance or growth-hormone results are inconsistent. A large retrospective older-adult cohort associated use with higher stroke risk; association does not establish causation.
Levels: how we grade evidence. Grey = evidence of no benefit; amber = evidence it makes this goal worse.
Ratings are self-reported by a self-selected group of users: how it felt, not proof that it works.
Check your bottle
Compare what your label says with what was used in trials. This is a trial range, not a personal prescription.
Enter the amount from your label to see the result.
How it was studied
UPPER LIMIT // The dossier quotes a US adult choline UL of 3,500 mg/day from all sources and no EFSA choline UL. That is not an Alpha-GPC safe-dose ceiling. Regulatory attribution was not independently confirmed, so no numerical Alpha-GPC UL is entered in the calculator.
Summary
Cognitive-disease studies suggest benefits, including in combinations with donepezil, but a nimodipine combination trial was negative. Healthy-adult evidence is narrow and physical-performance or growth-hormone results are inconsistent. A large retrospective older-adult cohort associated use with higher stroke risk; association does not establish causation.
Mechanism
Alpha-GPC supplies choline for acetylcholine and phospholipid pathways. More precursor does not guarantee better cognition; excess cholinergic activity can cause nausea, headache, sweating or diarrhea. Choline-to-TMAO metabolism is a proposed vascular mechanism, not established proof of causality.
Typical studied dose
The supplied MCI RCT used 600 mg/day for 12 weeks; dementia combinations used 1,200 mg/day, including 24 months with donepezil. Healthy-male acute studies used 315–630 mg; strength studies used 250–600 mg for six to seven days. These are Alpha-GPC compound doses, not elemental choline.
Upper limit
The dossier quotes a US adult choline UL of 3,500 mg/day from all sources and no EFSA choline UL. That is not an Alpha-GPC safe-dose ceiling. Regulatory attribution was not independently confirmed, so no numerical Alpha-GPC UL is entered in the calculator.
Popular stacks with Alpha-GPC
Not enough stack data yet. A combination with Alpha-GPC appears here once 5 people rate the same set.
Forms and label traps
| Form on label | Active content | Studied range / day | Absorption & GI tolerance | Verdict |
|---|---|---|---|---|
| Declared Alpha-GPC compound mass in capsules Best for: Comparing Alpha-GPC mass with acute healthy-male trial context. |
Extract weight · ~100% marker | 315–630 mg | Choline delivery is established; clinical superiority over every choline source is not. Headache, nausea, sweating or diarrhea can reflect excess cholinergic effects. |
Studied standard [REFERENCE // TRIAL_CONTEXT] The 315–630 mg range belongs to one small acute study, not a universal effective dose. About 41% choline content is separate from full-compound trial comparison. |
| 50% Alpha-GPC carrier powder: total powder mass Best for: Converting total powder mass to Alpha-GPC compound mass. |
50% elemental / active | 315–630 mg | Carrier fraction affects concentration and storage; superior bioavailability of a 99% product is unproven. Moisture uptake and clumping complicate weighing. |
Good option [FORM // CHECK_LABEL] A 600 mg amount of 50% powder supplies 300 mg Alpha-GPC, about 123 mg choline at 41%. |
| 99% Alpha-GPC powder: total powder mass Best for: Separating powder purity from choline fraction. |
99% elemental / active | 315–630 mg | Purity does not by itself establish superior clinical bioavailability. Adverse effects depend on actual exposure and individual response. |
Good option [FORM // CHECK_LABEL] A 600 mg amount of 99% powder supplies 594 mg Alpha-GPC. This is not 600 mg choline; about 41% of the Alpha-GPC mass is choline. |
Common label traps
- TRAP_01 // A proven growth-hormone muscle builder
Acute hormonal studies conflict, and the modern exercise RCT found no GH or physical-performance benefit. A hormone pulse is not evidence of hypertrophy. - TRAP_02 // 99% is far more bioavailable than 50%
These labels primarily describe Alpha-GPC versus carrier mass. Compare actual compound dose and storage, not a presumed efficacy multiplier. - TRAP_03 // Natural choline is completely safe
The observational stroke signal and cholinergic adverse effects require consideration; no causal certainty or risk-free dose follows from natural origin.
Other outcomes studied
Outside the five leaderboard goals. Same evidence levels as above.
- DEMENTIA: CLINICAL COGNITION Moderate · benefit
A 2023 review of seven RCTs and one cohort reported cognition MD 1.72 (95% CI 0.20–3.25) with donepezil and 3.50 (0.36–6.63) against placebo/other comparators; function MD 0.79 (0.34–1.23) and behavior MD -7.61 (-10.31 to -4.91). Several studies share a research group; this is clinical disease evidence.
PMID 36683513 PMID 11589921 PMID 24156263 - MILD COGNITIVE IMPAIRMENT Moderate · benefit
A 100-person 12-week RCT of 600 mg/day reported an ADAS-cog difference of -2.34 points. A 12-month nimodipine combination trial found no significant cognitive advantage; adherence and small sample limit interpretation.
PMID 39300341 PMID 29927403 PMID 33855653 - COMPARISON WITH CITICOLINE Limited · benefit
Three RCTs (n=358) favored Alpha-GPC on global SCAG score: WMD -3.92 (95% CI -7.41 to -0.42), but not isolated memory or verbal fluency; dropout difference was nonsignificant.
PMID 41426989 - ALZHEIMER BEHAVIORAL SYMPTOMS Moderate · benefit
In a 113-person trial, 1,200 mg/day with donepezil 10 mg over 24 months improved neuropsychiatric symptoms and caregiver distress versus donepezil alone. This is combination treatment in vascular-component Alzheimer disease.
PMID 28035924 PMID 35006557 - POST-STROKE RECOVERY Limited · benefit
Review findings suggest neurological recovery, but Alpha-GPC evidence is largely uncontrolled and cannot establish causation. This differs from primary stroke risk in the older-adult cohort.
PMID 37109211 PMID 11589921 - STRENGTH AND POWER Limited · benefit
A 13-person trial reported lower-body peak-force change +98.8 versus -39.0 N (p=0.044), with no upper-body benefit. A 48-person trial found no IMTP/UBIST difference but selected jump improvements; a newer acute trial found no physical-performance benefit.
PMID 26582972 PMID 29042830 PMID 39683633 - CYCLING: COMBINATION ONLY Limited · benefit
A 30-person crossover study of 8 g BCAA, 6 g citrulline and 300 mg Alpha-GPC reported peak power +11% and time-to-fatigue +36.2%; attribution to Alpha-GPC alone is impossible.
PMID 37229544 - HEALTHY-ADULT ACUTE COGNITION Limited · benefit
In 20 resistance-trained young men, 315/630 mg improved selected Stroop measures (d=0.48/0.61), but not Flanker, N-back, GH or physical performance; retrospective registration limits confidence.
PMID 39683633 - GROWTH HORMONE Limited · benefit
Older small pharmacodynamic studies reported a GHRH-response effect, while the modern exercise trial found no GH increase. Chronic muscle benefit is not established.
PMID 1577400 PMID 39683633 - AUTONOMIC RECOVERY Limited · benefit
One crossover RCT in 12 women with overweight/obesity reported quicker HRV and blood-pressure recovery after Wingate exercise with 1,000 mg; external validity is limited.
PMID 36235623
Reader questions
Does Alpha-GPC cause stroke?
The large Korean retrospective study found a dose-related association, not proof of causation. Participants were at least 50; the study cannot quantify a causal risk for every younger supplement user. The finding still matters when benefit is uncertain.
How do I compare a 50% powder with a capsule?
First establish whether the capsule label declares actual Alpha-GPC or total carrier powder. 600 mg of 50% powder gives 300 mg Alpha-GPC; neither figure equals choline mass.
What if it causes headache, low mood or brain fog?
These symptoms do not diagnose a choline deficiency or prove a need for more. Cholinergic adverse effects and reader mood reports warrant reassessment, particularly with psychiatric or cholinergic drugs.
Stack interactions
- Caution Donepezil, rivastigmine and huperzine A [CAUTION // CLINICAL_REVIEW]
Additive cholinergic activity can cause nausea, headache, sweating, dizziness or diarrhea. Donepezil combinations were studied clinically; that does not validate unsupervised supplement stacking.
PMID 28035924 - Caution High vascular risk or antithrombotic treatment [CAUTION // CLINICAL_REVIEW]
The older-adult stroke association is relevant to risk review, but it is not evidence of a direct anticoagulant interaction.
PMID 34817582 - Caution Thyroid disease or levothyroxine [CAUTION // CLINICAL_REVIEW]
A 500 mg study reported lower TSH. This exploratory signal does not prove a clinically significant drug interaction.
PMID 29042830 - Caution Racetams or stimulant pre-workouts [CAUTION // CLINICAL_REVIEW]
Clinical superiority of these stacks is not established here. More choline may add adverse effects rather than prevent every racetam-related headache.
Red flags: interactions and who should avoid it
Interactions
Donepezil, rivastigmine and huperzine A can add cholinergic effects; intentional clinical combinations need oversight. The stroke association is a population safety signal, not a demonstrated anticoagulant interaction. A small trial TSH signal is not proof of a thyroid-drug interaction. Racetam and caffeine stacks lack proven Alpha-GPC-specific synergy.
Avoid or ask a doctor first if
Pregnancy, breastfeeding, age under 18, thyroid disease, depression or high vascular/stroke risk require individual assessment. In the Korean retrospective cohort of 12,008,977 adults aged at least 50, stroke aHR was 1.43 (95% CI 1.41–1.46), ischemic 1.34 and hemorrhagic 1.37, with a dose-response association. Confounding remains possible. New neurological symptoms require urgent medical evaluation.
Sources (PubMed, 19)
- Activity of Choline Alphoscerate on Adult-Onset Cognitive Dysfunctions: A Systematic Review and Meta-Analysis.
PMID 36683513 · 2023 · Meta-analysisA 2023 review of seven RCTs and one cohort reported cognition MD 1.72 (95% CI 0.20–3.25) with donepezil and 3.50 (0.36–6.63) against placebo/other comparators; function MD 0.79 (0.34–1.23) and behavior MD -7.61 (-10.31 to -4.91). Several studies share a research group; this is clinical disease evidence.
- Choline alphoscerate in cognitive decline and in acute cerebrovascular disease: an analysis of published clinical data.
PMID 11589921 · 2001 · Clinical or pharmacokinetic reportA 2023 review of seven RCTs and one cohort reported cognition MD 1.72 (95% CI 0.20–3.25) with donepezil and 3.50 (0.36–6.63) against placebo/other comparators; function MD 0.79 (0.34–1.23) and behavior MD -7.61 (-10.31 to -4.91). Several studies share a research group; this is clinical disease evidence. Review findings suggest neurological recovery, but Alpha-GPC evidence is largely uncontrolled and cannot establish causation. This differs from primary stroke risk in the older-adult cohort.
- Choline alphoscerate (alpha-glyceryl-phosphoryl-choline) an old choline- containing phospholipid with a still interesting profile as cognition enhancing agent.
PMID 24156263 · 2013 · Clinical or pharmacokinetic reportA 2023 review of seven RCTs and one cohort reported cognition MD 1.72 (95% CI 0.20–3.25) with donepezil and 3.50 (0.36–6.63) against placebo/other comparators; function MD 0.79 (0.34–1.23) and behavior MD -7.61 (-10.31 to -4.91). Several studies share a research group; this is clinical disease evidence.
- Efficacy and safety of choline alphoscerate for amnestic mild cognitive impairment: a randomized double-blind placebo-controlled trial.
PMID 39300341 · 2024 · Randomized controlled trialA 100-person 12-week RCT of 600 mg/day reported an ADAS-cog difference of -2.34 points. A 12-month nimodipine combination trial found no significant cognitive advantage; adherence and small sample limit interpretation.
- [Clinical efficacy and safety of choline alfoscerate in the treatment of late-onset cognitive impairment].
PMID 29927403 · 2018 · Clinical or pharmacokinetic reportA 100-person 12-week RCT of 600 mg/day reported an ADAS-cog difference of -2.34 points. A 12-month nimodipine combination trial found no significant cognitive advantage; adherence and small sample limit interpretation.
- Efficacy and Safety of the Association of Nimodipine and Choline Alphoscerate in the Treatment of Cognitive Impairment in Patients with Cerebral Small Vessel Disease. The CONIVaD Trial.
PMID 33855653 · 2021 · Randomized controlled trialA 100-person 12-week RCT of 600 mg/day reported an ADAS-cog difference of -2.34 points. A 12-month nimodipine combination trial found no significant cognitive advantage; adherence and small sample limit interpretation.
- Comparison of the effects of choline alphoscerate and citicoline in patients with dementia disorders: a systematic review and meta-analysis.
PMID 41426989 · 2025 · Systematic reviewThree RCTs (n=358) favored Alpha-GPC on global SCAG score: WMD -3.92 (95% CI -7.41 to -0.42), but not isolated memory or verbal fluency; dropout difference was nonsignificant.
- The Effect of the Association between Donepezil and Choline Alphoscerate on Behavioral Disturbances in Alzheimer's Disease: Interim Results of the ASCOMALVA Trial.
PMID 28035924 · 2017 · Randomized controlled trialIn a 113-person trial, 1,200 mg/day with donepezil 10 mg over 24 months improved neuropsychiatric symptoms and caregiver distress versus donepezil alone. This is combination treatment in vascular-component Alzheimer disease. Additive cholinergic activity can cause nausea, headache, sweating, dizziness or diarrhea. Donepezil combinations were studied clinically; that does not validate unsupervised supplement stacking.
- Pharmacological Management of Apathy in Dementia.
PMID 35006557 · 2022 · Clinical or pharmacokinetic reportIn a 113-person trial, 1,200 mg/day with donepezil 10 mg over 24 months improved neuropsychiatric symptoms and caregiver distress versus donepezil alone. This is combination treatment in vascular-component Alzheimer disease.
- Choline-Containing Phospholipids in Stroke Treatment: A Systematic Review and Meta-Analysis.
PMID 37109211 · 2023 · Clinical or pharmacokinetic reportReview findings suggest neurological recovery, but Alpha-GPC evidence is largely uncontrolled and cannot establish causation. This differs from primary stroke risk in the older-adult cohort.
- The effect of 6 days of alpha glycerylphosphorylcholine on isometric strength.
PMID 26582972 · 2015 · Randomized controlled trialA 13-person trial reported lower-body peak-force change +98.8 versus -39.0 N (p=0.044), with no upper-body benefit. A 48-person trial found no IMTP/UBIST difference but selected jump improvements; a newer acute trial found no physical-performance benefit.
- Evaluation of the effects of two doses of alpha glycerylphosphorylcholine on physical and psychomotor performance.
PMID 29042830 · 2017 · Randomized controlled trialA 13-person trial reported lower-body peak-force change +98.8 versus -39.0 N (p=0.044), with no upper-body benefit. A 48-person trial found no IMTP/UBIST difference but selected jump improvements; a newer acute trial found no physical-performance benefit. A 500 mg study reported lower TSH. This exploratory signal does not prove a clinically significant drug interaction.
- Acute Alpha-Glycerylphosphorylcholine Supplementation Enhances Cognitive Performance in Healthy Men.
PMID 39683633 · 2024 · Randomized controlled trialA 13-person trial reported lower-body peak-force change +98.8 versus -39.0 N (p=0.044), with no upper-body benefit. A 48-person trial found no IMTP/UBIST difference but selected jump improvements; a newer acute trial found no physical-performance benefit. In 20 resistance-trained young men, 315/630 mg improved selected Stroop measures (d=0.48/0.61), but not Flanker, N-back, GH or physical performance; retrospective registration limits confidence. Older small pharmacodynamic studies reported a GHRH-response effect, while the modern exercise trial found no GH increase. Chronic muscle benefit is not established. Form or pharmacokinetic context: The 315–630 mg range belongs to one small acute study, not a universal effective dose. About 41% choline content is separate from full-compound trial comparison.
- Effects of branched chain amino acids, l-citrulline, and alpha-glycerylphosphorylcholine supplementation on exercise performance in trained cyclists: a randomized crossover trial.
PMID 37229544 · 2023 · Randomized controlled trialA 30-person crossover study of 8 g BCAA, 6 g citrulline and 300 mg Alpha-GPC reported peak power +11% and time-to-fatigue +36.2%; attribution to Alpha-GPC alone is impossible.
- alpha-Glycerylphosphorylcholine administration increases the GH responses to GHRH of young and elderly subjects.
PMID 1577400 · 1992 · Clinical or pharmacokinetic reportOlder small pharmacodynamic studies reported a GHRH-response effect, while the modern exercise trial found no GH increase. Chronic muscle benefit is not established.
- The Effects of Alpha-Glycerylphosphorylcholine on Heart Rate Variability and Hemodynamic Variables Following Sprint Interval Exercise in Overweight and Obese Women.
PMID 36235623 · 2022 · Randomized controlled trialOne crossover RCT in 12 women with overweight/obesity reported quicker HRV and blood-pressure recovery after Wingate exercise with 1,000 mg; external validity is limited.
- L-Alpha-Glycerylphosphorylcholine (L-α-GPC): A Comprehensive Review of Its Preparation Techniques and Versatile Biological Effects.
PMID 40556032 · 2025 · Clinical or pharmacokinetic reportForm or pharmacokinetic context: A 600 mg amount of 50% powder supplies 300 mg Alpha-GPC, about 123 mg choline at 41%.
- Unlocking the Potential of l-α-Glycerylphosphorylcholine: From Metabolic Pathways to Therapeutic Applications.
PMID 40036805 · 2025 · Clinical or pharmacokinetic reportForm or pharmacokinetic context: A 600 mg amount of 99% powder supplies 594 mg Alpha-GPC. This is not 600 mg choline; about 41% of the Alpha-GPC mass is choline.
- Association of L-α Glycerylphosphorylcholine With Subsequent Stroke Risk After 10 Years.
PMID 34817582 · 2021 · Clinical or pharmacokinetic reportThe older-adult stroke association is relevant to risk review, but it is not evidence of a direct anticoagulant interaction.
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