Scientific Studies and References
The Research Behind eudopa™
This page compiles the clinical and preclinical research relevant to eudopa™'s three ingredients: citicoline, wild blueberry extract, and phosphatidylserine.
Studies are organized into two tiers. Anchor studies — the highest-quality, most directly relevant trials — are presented in full detail, including dose, findings, and limitations. Supporting studies are summarized in compact form and labeled by study type.
Where a study used a different formulation or dose than what's in eudopa™, we note it.
CDP-Choline (Citicoline) Memory · Focus · Neuroprotection · Stroke Recovery 21 studies
Memory
Tier 1 — Anchor Study
Journal of Nutrition
PMID: 33978188
What They Studied
A 12-week randomized, double-blind, placebo-controlled trial in 100 healthy US adults aged 18–60 examining whether citicoline supplementation improves memory and attention.
What They Found
Participants taking 500mg citicoline daily showed significant improvements in episodic memory (recall of recent events) compared to placebo. Effects were most pronounced in adults over 50.
Dose Used
500mg/day ✓ Matches eudopa's 500mg dose
Relevance to eudopa
This is the most rigorous RCT on citicoline in healthy adults using the exact dose in eudopa. It directly supports the 500mg dose choice.
What to Know
Study was funded by Kyowa Hakko Bio Co., which manufactures Cognizin® citicoline — a potential source of bias. Results were statistically significant and effect sizes were moderate.
Tier 1 — Anchor Study
Journal of Attention Disorders
PMID: 26179181
What They Studied
A 28-day RCT in 60 healthy adolescent females (15–24 years old) testing whether citicoline supplementation improves attention and psychomotor speed.
What They Found
250mg and 500mg citicoline both produced significant improvements in attentional performance and reduced impulsivity compared to placebo.
Dose Used
250mg and 500mg → eudopa uses 500mg (higher of the two doses tested)
Relevance to eudopa
Demonstrates cognitive benefit in a younger healthy population, not just older adults — broadening relevance of eudopa's 500mg dose.
What to Know
All-female sample limits generalizability to mixed or male populations. Short 28-day duration. Funded by Kyowa Hakko.
Tier 1 — Anchor Study
Cochrane Database of Systematic Reviews
PMID: 15846601
What They Studied
A Cochrane systematic review of 14 RCTs examining citicoline's effect on cognitive decline in elderly populations, primarily those with memory impairment or early-stage cognitive deterioration.
What They Found
Consistent positive effects on memory and cognitive function across all trials reviewed. The evidence quality was moderate; results were strongest for memory and attention domains.
Dose Used
Varied across trials (300–1000mg) → eudopa uses 500mg; within the studied range
Relevance to eudopa
Provides the broadest evidence base for citicoline's effect on memory — 14 trials pointing in the same direction strengthens confidence in citicoline as a memory support ingredient.
What to Know
Most trials in this review focused on populations with cognitive impairment, not healthy adults. Effects in healthy, younger individuals may be smaller.
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Alvarez XA et al. (1997)PMID: 9203170
RCT 30 Alzheimer's patients · Citicoline 1000mg/day improved cognitive test scores Population context — disease
Spiers PA et al. (1996)PMID: 8624220
RCT Older adults with memory impairment · Verbal memory improvements with citicoline Population context
Mosharrof AH et al. (1986)PMID: 3129903
Clinical Trial Adult patients · Positive memory effects with citicoline injection Dose context — IV form, not oral
Putignano S et al. (2017)PMID: 28035929
Clinical Trial Older adults with mild cognitive impairment · Combined citicoline + donepezil improved cognition beyond drug alone Population context — disease
Attention / Focus
Tier 1 — Anchor Study
NMR in Biomedicine
PMID: 18816480
What They Studied
A 6-week open-label pilot trial using MR spectroscopy to measure how citicoline affects brain energy metabolism and neurochemistry in healthy older adults.
What They Found
500mg citicoline daily significantly increased phosphocreatine (brain energy reserves) and altered choline-containing compounds — measurable signs of enhanced membrane phospholipid synthesis. Anxiety scores also decreased.
Dose Used
500mg/day ✓ Matches eudopa's 500mg dose
Relevance to eudopa
Provides direct neuroimaging evidence for how citicoline supports brain function at the cellular level — not just behavioral test scores, but measurable biological changes at the exact dose in eudopa.
What to Know
Open-label design (no blinding) and small sample size. Valuable for mechanistic understanding of how citicoline supports brain energy; should not be read as a controlled efficacy trial.
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Secades JJ, Frontera G (1995)PMID: 8709678
Review Comprehensive review of citicoline across cognitive domains · Positive effects on attention consistently observed Mechanism support
Knott V et al. (2015)PMID: 25700947
RCT Healthy adults; EEG outcomes · Citicoline altered P300 event-related potentials, suggesting attentional effects at neural level Mechanism support
Alzheimer's & Dementia
The studies in this section examine these ingredients in research populations that include individuals with the conditions listed. This research is provided for educational and scientific context only. eudopa™ is not intended to diagnose, treat, cure, or prevent any disease or medical condition.
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Fioravanti M, Buckley AE (2006)PMID: 18046877
Systematic Review Alzheimer's and vascular dementia populations · Citicoline showed benefit in multiple cognitive domains Population context — disease
Leon-Carrion J et al. (2000)PMID: 11455066
Clinical Trial Brain-injured patients · Citicoline improved cognitive recovery outcomes Population context — disease
Alvarez XA et al. (1997)PMID: 9203170
RCT Alzheimer's patients · Citicoline 1000mg improved MMSE scores Population context — disease
Parkinson's Disease
The studies in this section examine these ingredients in research populations that include individuals with the conditions listed. This research is provided for educational and scientific context only. eudopa™ is not intended to diagnose, treat, cure, or prevent any disease or medical condition.
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Secades JJ (2011)PMID: 21432836
Review Parkinson's patients; adjunct therapy · Citicoline as adjunct to levodopa showed cognitive and motor benefits Population context — disease
Eberhardt R et al. (1990)PMID: 2289218
Clinical Trial Parkinson's patients · Citicoline improved early-stage PD symptoms Population context — disease
Stroke Recovery
The studies in this section examine these ingredients in research populations that include individuals with the conditions listed. This research is provided for educational and scientific context only. eudopa™ is not intended to diagnose, treat, cure, or prevent any disease or medical condition.
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Clark WM et al. (1997)PMID: 9305321
RCT Ischemic stroke patients · Citicoline improved neurological outcomes at 500mg–2000mg/day Population context — disease, Dose context
Warach S et al. (2000)PMID: 11079534
RCT Acute ischemic stroke · Citicoline reduced lesion volume in diffusion-weighted MRI Population context — disease
Dávalos A et al. (2002)PMID: 12468781
Meta-Analysis Stroke patients; pooled trial data · Citicoline associated with improved functional recovery Population context — disease
Secades JJ et al. (2006)PMID: 17171187
Review Stroke recovery; post-stroke cognitive impairment · Citicoline supported neurological recovery across multiple mechanisms Mechanism support
Remyelination / Nerve Repair
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Levin HS (1991)PMID: 1940965
Review Animal and human data · Citicoline supports myelin sheath synthesis; relevant to MS and nerve injury contexts Mechanism support
Appetite
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Killgore WDS et al. (2010)PMID: 19260039
Clinical Trial Healthy women · 500mg citicoline reduced appetite and food cravings via dopaminergic pathways Mechanism support
Phosphatidylserine Stress · Memory · ADHD · Mood 14 studies
Formulation note: eudopa™ provides 100mg active phosphatidylserine per serving — at the lower end of clinical study ranges (most trials used 200–400mg), but supported by research at this dose and sufficient for most people as part of a daily foundation stack. For those with unique cognitive demands or performance needs, eudopa™ is designed to be taken up to 3 servings daily, reaching the 200–300mg range used in many clinical trials.
Stress & Cortisol
Tier 1 — Anchor Study
Lipids in Health and Disease
PMID: 25081826
What They Studied
A double-blind, placebo-controlled RCT in 75 moderately stressed healthy adults testing whether a phosphatidylserine/phosphatidic acid (PS/PA) complex reduces perceived stress and cortisol reactivity over 3 weeks.
What They Found
PS/PA supplementation significantly reduced perceived stress and blunted cortisol response to acute mental stress compared to placebo.
Dose Used
400mg PS/PA complex → eudopa provides 100mg active PS per serving; this study used a higher-dose compound form
Relevance to eudopa
The most rigorous modern RCT on PS and stress in healthy adults. Demonstrates the stress-modulating mechanism that makes PS a logical inclusion in a daily nootropic.
What to Know
Study used a PS/PA complex (phosphatidylserine + phosphatidic acid) rather than plain soy-derived PS. The addition of phosphatidic acid may contribute to effects. eudopa uses plain soy-derived PS — effects at 100mg active PS may differ from this compound formulation at 400mg.
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Baumeister J et al. (2008)PMID: 18616866
Clinical Trial Healthy adults; EEG after mental stress · PS altered cortical EEG patterns following acute stress exposure Mechanism support
Monteleone P et al. (1990)PMID: 2170852
RCT Healthy adults; exercise stress · Bovine PS blunted exercise-induced ACTH and cortisol rise Dose context Formulation note — see caveat
Monteleone P et al. (1992)PMID: 1325348
RCT Healthy men · Bovine PS dose-dependently reduced cortisol response to physical stress Dose context Formulation note — see caveat
Memory
Tier 1 — Anchor Study
Neurology
PMID: 2027477
What They Studied
A 12-week randomized, double-blind, placebo-controlled trial in 149 adults (50–75 years) with age-associated memory impairment, testing whether bovine-derived PS improved memory and cognitive function.
What They Found
PS supplementation significantly improved learning tasks, memory retrieval, and overall cognitive test performance compared to placebo. Participants who had showed greater decline at baseline benefited most.
Dose Used
300mg/day → eudopa provides 100mg active PS; this study used 300mg of bovine-derived PS
Relevance to eudopa
One of the landmark PS trials establishing its memory-supporting mechanism. Study population (cognitively declining older adults) differs from eudopa's primary target, but the mechanism — PS supporting neuronal membrane integrity and acetylcholine release — applies broadly.
What to Know
Bovine cortex PS (bcPS) was used, which has a different phospholipid profile from eudopa's soy-derived PS. Bovine PS is no longer commercially available due to BSE concerns. Effects of soy-derived PS may be smaller than this study suggests.
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Kato-Kataoka A et al. (2010)PMID: 21103034
RCT Elderly Japanese adults with mild cognitive decline · Soy-derived PS (100mg) improved memory function over 6 months. Notable: used soy-derived PS at 100mg — closest formulation match to eudopa Population context, Dose context
Glade MJ, Smith K (2015)PMID: 25933483
Review Comprehensive narrative review of PS research in humans · PS consistently supports memory, learning, and concentration across populations Mechanism support
Vakhapova V et al. (2010)PMID: 20523044
RCT Elderly adults with memory complaints · PS-DHA complex improved delayed verbal recall Population context Formulation note — see caveat
Vakhapova V et al. (2014)PMID: 24577097
RCT Elderly adults at risk for dementia · PS-omega3 complex slowed cognitive decline Population context Formulation note — see caveat
Schreiber S et al. (2000)PMID: 11201936
RCT Elderly adults with age-related cognitive decline · PS-DHA combination improved cognitive scores Population context — disease Formulation note — see caveat
ADHD
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Hirayama S et al. (2014)PMID: 23495677
RCT Children with ADHD · Soy-derived PS improved attention and ADHD symptom scores Population context
Manor I et al. (2011)PMID: 21807480
RCT Children with ADHD · PS + omega-3 improved behavioral outcomes Population context Formulation note — see caveat
Moré MI et al. (2014)PMID: 25414047
RCT Elderly adults with cognitive complaints · PS + phosphatidic acid improved memory, daily functioning, and mood Population context Formulation note — see caveat
Depression / Mood
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Komori T (2015)PMID: 26266022
Clinical Trial Elderly adults with depressive symptoms · PS + DHA + EPA combination improved mood scores Population context Formulation note — see caveat
Wild Blueberry Extract Cognitive Enhancement · Memory · BDNF 16 studies
Cognitive Enhancement
Tier 1 — Anchor Study
Applied Physiology, Nutrition, and Metabolism
PMID: 28249119
What They Studied
A 12-week double-blind, placebo-controlled RCT in 26 healthy older adults (65–77 years) examining whether whole blueberry supplementation improves brain perfusion and cognitive function using functional MRI.
What They Found
Blueberry supplementation significantly improved brain perfusion (blood flow) in areas associated with cognitive function, and produced better scores on cognitive tests. fMRI showed increased activation in memory-related brain regions.
Dose Used
30g freeze-dried whole blueberry (equivalent to ~230g fresh blueberries, delivering substantial anthocyanins) → eudopa uses 250mg wild blueberry extract; standardized extracts provide concentrated anthocyanins from a smaller mass
Relevance to eudopa
Provides direct imaging evidence of how blueberry anthocyanins affect brain blood flow and function. Demonstrates the cerebrovasculature mechanism underlying cognitive effects — relevant to eudopa's blueberry extract inclusion.
What to Know
Whole berry dose is not directly comparable to an extract. Anthocyanin content of eudopa's 250mg wild blueberry extract vs. the whole berry dose in this study requires context. Small sample (n=26). Older adult population only.
Tier 1 — Anchor Study
Nutrients
PMID: 29882843
What They Studied
A 12-week RCT in 122 healthy older adults (65–80 years) examining the effect of 500mg blueberry extract on cognitive function, mood, and blood pressure.
What They Found
Blueberry extract significantly improved spatial working memory, with benefits sustained across the 12-week trial. Mood and blood pressure effects were non-significant.
Dose Used
500mg blueberry extract → eudopa uses 250mg; this study used 500mg extract
Relevance to eudopa
Largest RCT specifically using blueberry extract (not whole berry) in healthy older adults. Shows cognitive benefits at extract form, which is more directly comparable to eudopa than whole berry studies.
What to Know
eudopa uses half the dose used in this trial. The dose-response relationship for blueberry anthocyanins is not fully established, so it's unclear whether 250mg produces half the effect or less.
Tier 1 — Anchor Study
Brain, Behavior, and Immunity
PMID: 30999017
What They Studied
A systematic review of 12 randomized controlled trials examining the effect of blueberry supplementation on human cognitive function across age groups.
What They Found
The majority of reviewed trials reported positive effects of blueberry supplementation on at least one cognitive domain, particularly memory and executive function. Evidence quality was moderate; more high-quality trials are needed.
Dose Used
Varied across 12 trials → eudopa's 250mg extract falls within the range studied across trials
Relevance to eudopa
Provides the clearest overall evidence synthesis for blueberry supplementation and cognitive function — 12 trials, multiple populations, broadly positive findings support inclusion of blueberry extract in a cognitive supplement.
What to Know
Heterogeneity in study designs, populations, doses, and outcome measures limits definitive conclusions. Most trials had small samples. The authors note that standardized anthocyanin dosing across trials would improve evidence quality.
Memory
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Krikorian R et al. (2010)PMID: 20047325
Clinical Trial Older adults with early memory decline · Daily blueberry juice improved paired-associate learning and word list recall Population context
McNamara RK et al. (2018)PMID: 29458842
RCT Healthy older adults · Combined blueberry + fish oil did not produce expected cognitive enhancement. Does not negate isolated blueberry evidence, but relevant for combination formulas. Null finding
Devore EE et al. (2012)PMID: 22535616
Observational Nurses' Health Study; large female cohort · Higher long-term berry flavonoid intake associated with slower cognitive decline (up to 2.5 years' delay) Population context, Mechanism support
Miller MG et al. (2018)PMID: 28283823
RCT Healthy older adults · Freeze-dried blueberry powder improved memory and psychomotor speed Population context
Neuroprotection / BDNF
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Rendeiro C et al. (2013)PMID: 23723987
Animal Model Aged rats · Blueberry supplementation reversed age-related spatial memory decline and increased hippocampal BDNF Animal model — mechanism only
Ebenezer PJ et al. (2016)PMID: 27603014
Animal Model Rodent model · Blueberry extract reduced neuroinflammation and oxidative damage in the brain Animal model — mechanism only
Krishna G, Ying Z, Gomez-Pinilla F (2019)PMID: 31115168
Animal Model Rodent model · Dietary blueberry improved BDNF signaling and cognitive function in aged rats Animal model — mechanism only
Fang Z et al. (2022)PMID: 35651724
Animal Model Aged mouse model · Blueberry polyphenols improved neuroplasticity markers and spatial learning Animal model — mechanism only
Williams CM et al. (2008)PMID: 18457678
Animal Model Rodent model · Flavonoid-rich blueberry diet enhanced hippocampal BDNF expression Animal model — mechanism only
Çoban J et al. (2015)PMID: 25511550
Animal Model Rat model · Blueberry extract reduced homocysteine-induced oxidative brain damage Animal model — mechanism only
Inflammation
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Subash S et al. (2014)PMID: 25317174
Review Narrative review of berry fruits in neurodegeneration · Examines polyphenol mechanisms across blueberry, strawberry, and other berries Review
Shukitt-Hale B et al. (2015)PMID: 26392037
Review Aging populations and neuroinflammation · Blueberry polyphenols modulate microglial activation and reduce oxidative stress Mechanism support
Afzal M et al. (2019)PMID: 31766696
Review Human and animal data · Blueberry anthocyanins and neuroprotection via anti-inflammatory and antioxidant mechanisms Mechanism support