Phosphatidylserine

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1. What Phosphatidylserine Is

Phosphatidylserine is a phospholipid membrane component found in all animal and plant cells. Natural sources include soya, sunflower seeds, and animal tissues such as brain or liver. In the human body, it is primarily located in the inner layer of the cell membrane and plays a key role in signal transduction, apoptosis, and the interaction between cells and the immune system.

For understanding the evidence base, it is crucial that phosphatidylserine is rarely studied in isolation. It is frequently used in combination with phosphatidic acid or omega-3 fatty acids, which complicates the attribution of effects. Additionally, bioavailability and metabolic utilisation differ depending on the formulation (e.g., as powder, capsule, or in liposomes). Measuring phosphatidylserine in blood or tissue is methodologically challenging, as it is rapidly converted into other phospholipids or incorporated into cell membranes. Many studies therefore use surrogate markers, such as the phagocytic activity of microglia or cognitive test batteries, whose validity is limited.

2. What the Studies Show in Detail

The key human studies and most important reviews — by area of application, including population, duration, preparation, outcome measures, and results, as reported in the original publications. Numbers are only provided where the study specifies them.

Distribution of controlled human trials by area of application — the numbers are not additive, as a single study may be assigned to multiple areas:

Cognition and Psyche

In a randomised, double-blind pilot study (2016), 15 postmenopausal women (aged 60–84) received a multinutrient supplement (Efalex Active 50+) for 6 months, which included 60 mg of phosphatidylserine per day. The control group (N = 12) received a placebo. Cognitive performance was measured using computer-assisted tests, mobility via the VICON-9 camera system and force plates, and blood levels of fatty acids. The supplement led to significantly shorter reaction times in a motor screening test (p < 0.05) and improved word memory performance (p < 0.03). Additionally, habitual walking speed increased (p < 0.05). Limitations include the small sample size and the combination with other active ingredients (e.g., DHA, Ginkgo biloba), which precludes isolating the effect of phosphatidylserine within the multinutrient supplement.

A randomised, double-blind study (2010) investigated the effect of a phosphatidylserine-omega-3 complex (PS-DHA) in 157 non-demented older participants with subjective memory complaints. Over 15 weeks, participants received daily PS-DHA or placebo. Primary endpoints included cognitive tests (Rey Auditory Verbal Learning Test, Rey Complex Figure Test, computerised battery). A post-hoc analysis revealed that participants with relatively good baseline cognitive performance additionally benefited from improvements in delayed recall, learning ability, and the time taken to copy complex figures. The study suggests a dose-dependent effect of the PS-DHA complex, though the combination with omega-3 limits the generalisability to the specific effects of this complex 1.

In a randomised, double-blind study (2014), the effect of a soy lecithin-derived phosphatidylserine-phosphatidic acid complex (PS+PA, 300 mg PS + 240 mg PA/day) was examined in 84 older participants with Alzheimer’s dementia over 2 months. The verum group (PP n = 53) showed no deterioration in 7 activities of daily living (ADL), whereas the placebo group (PP n = 39) exhibited a significant decline from 5.62 to 4.90 points (p = 0.035). The results provide a hint for the PS+PA complex but are not interpretable for phosphatidylserine alone due to the combination with phosphatidic acid 2.

A randomised, double-blind study (2014) assessed the effect of 200 mg/day soy-derived phosphatidylserine in 36 children (aged 4–14) with ADHD over 2 months. The verum group (n = 19) demonstrated significant improvements in ADHD symptoms (p < 0.01), attention deficit (p < 0.01), and hyperactivity (p < 0.01), as well as in auditory short-term memory (Digit Span Test, p < 0.05). The placebo group (n = 17) showed no significant changes. The study suggests that phosphatidylserine may alleviate ADHD symptoms, though long-term data and differentiation by ADHD subtypes are lacking 3.

Hypothesis The studies indicate a potential cognitive effect of phosphatidylserine, particularly in mild cognitive impairment, ADHD, and early-stage dementia. However, the effects are often only detectable in subgroups or in studies combining phosphatidylserine with other active ingredients (e.g., omega-3, phosphatidic acid). A clear dose-response relationship or a uniform mechanism of action is lacking. It remains unclear whether the observed effects in these combinations are attributable to phosphatidylserine, the additional substances, or their interaction.

What is lacking: Long-term studies with larger sample sizes examining pure phosphatidylserine preparations at various dosages and in specific cognitive deficits (e.g., executive functions, working memory). Additionally, studies directly measuring the influence of phosphatidylserine on neuronal plasticity or neurotransmitter systems (e.g., acetylcholine, dopamine) are needed.

Overall Picture

3. How Robust the Research Is

Research on phosphatidylserine is divided into three main areas: basic research, observational human studies, and controlled clinical trials. The controlled trials focus on three areas of application: cognition, metabolism, and fatigue. Additional studies examine cardiovascular effects, safety, and immune modulation. Notably, no area of application is covered by a large number of controlled studies. The controlled studies from 2010–2024 primarily investigate cognitive parameters in older participants or stress reactivity.

The robustness of the data is limited by several factors. Firstly, the number of controlled studies per area of application is small, making quantitative syntheses challenging. Secondly, many studies are combined with other substances (e.g., omega-3 fatty acids), which complicates the causal attribution of effects. Thirdly, long-term data on safety and efficacy are lacking. Fourthly, the target groups are often narrowly defined (e.g., older individuals with subjective memory complaints), which limits generalizability. While basic scientific studies demonstrate plausible mechanisms (e.g., modulation of microglial activity), the translation into clinical application remains speculative.

4. Common Claims and the Evidence

5. The Most Robust Studies

Ranked by evidential strength, not by prominence. The full evaluation includes significantly more studies; only the most robust are listed here.

Controlled Human Studies

• A High Omega-3 Fatty Acid Multinutrient Supplement Benefits Cognition and Mobility in Older Women: A Randomized, Double-blind, Placebo-controlled Pilo (2016)
• 1 Phosphatidylserine containing omega-3 fatty acids may improve memory abilities in non-demented elderly with memory complaints: a double-blind placebo- (2010)
• 2 Positive effects of soy lecithin-derived phosphatidylserine plus phosphatidic acid on memory, cognition, daily functioning, and mood in elderly patien (2014)
• 3 The effect of phosphatidylserine administration on memory and symptoms of attention-deficit hyperactivity disorder: a randomised, double-blind, placeb (2014)
• Ticagrelor attenuates the increase of extracellular vesicle concentrations in plasma after acute myocardial infarction compared to clopidogrel (2020)
• Randomised phase III study of docetaxel plus bavituximab in previously treated advanced non-squamous non-small-cell lung cancer (2018)
• 4 The phosphatidylserine-targeting antibody bavituximab plus pembrolizumab in unresectable hepatocellular carcinoma: a phase 2 trial (2024)
• 5 Effects of phosphatidylserine on the neuroendocrine response to physical stress in humans (1990)
• 6 Blunting of the stress-induced activation of the hypothalamic-pituitary-adrenal axis in healthy men by chronic phosphatidylserine administration (1992)
• 7 Omega-3 fatty acids administered in phosphatidylserine improved certain aspects of high chronic stress in men (2012)
• Effects of lipid-lowering treatment on circulating microparticles in patients with diabetes mellitus and chronic kidney disease (2016)
• 8 A soy-based phosphatidylserine/phosphatidic acid complex (PAS) normalises the stress reactivity of the hypothalamus-pituitary-adrenal axis in chronic stress (2014)
• Docetaxel combined with bavituximab in previously treated, advanced non-squamous non-small-cell lung cancer (2016)
• How to diagnose and manage antiphospholipid syndrome (2023)
• 9 Safety of phosphatidylserine containing omega-3 fatty acids in children with ADHD: a double-blind placebo-controlled trial followed by an open-label extension (2013)
• The effects of IQPLUS Focus on cognitive function, mood and endocrine response before and following acute exercise (2011)
• 10 Phosphatidylserine for the treatment of paediatric attention-deficit/hyperactivity disorder: a systematic review and meta-analysis (2021)
• 11 A lecithin phosphatidylserine and phosphatidic acid complex (PAS) reduces symptoms of premenstrual syndrome (PMS): results of a randomised, placebo-controlled trial (2018)
• Profile of bavituximab and its potential in the treatment of non-small-cell lung cancer (2014)
• 12 Phosphatidylserine enriched with polyunsaturated n-3 fatty acid supplementation for attention-deficit hyperactivity disorder in children and adolescents (2024)
• Acute supplementation with an amino acid mixture suppressed the exercise-induced cortisol response in recreationally active healthy volunteers: a randomised controlled trial (2020)
• Combining a high-DHA multi-nutrient supplement with aerobic exercise: protocol for a randomised controlled study assessing mobility and cognitive function (2019)
• 13 Effects of a food supplement containing phosphatidylserine on cognitive function in Chinese older adults with mild cognitive impairment: a randomised controlled trial (2025)
• Impact of a plant sterol food supplement on eryptotic and associated cardiometabolic parameters: a randomised placebo-controlled trial in statin-treated patients (2024)

6. Summary

Controlled studies on phosphatidylserine primarily focus on cognitive effects, particularly in older participants with subjective memory complaints or mild cognitive impairment, as well as in children with ADHD. The most robust findings demonstrate improvements in cognitive test batteries, reaction times, and activities of daily living in studies combining phosphatidylserine with other substances such as omega-3 fatty acids or phosphatidic acid. The evidence on stress reactivity suggests a potential modulation of the hypothalamic-pituitary-adrenal axis in these combinations, while data on cardiovascular disease, immune modulation, or antioxidant effects remain insufficient to draw reliable conclusions. The methodological quality of the studies is limited by small sample sizes, heterogeneous populations, and the use of surrogate markers.

Hypothesis The observed cognitive effects may be attributable to modulation of membrane fluidity or an indirect neuroprotective effect of phosphatidylserine, particularly when combined with omega-3 fatty acids. A role in regulating microglial activity and neuroinflammation also appears plausible, as suggested by basic science research. Should these mechanisms be confirmed, phosphatidylserine could in future play a role as a supportive measure in mild cognitive impairment or stress-related dysregulation. However, it remains unclear whether the substance crosses the blood-brain barrier in effective concentrations or whether the effects are due to systemic actions (e.g., stress reduction).

To clarify the clinical relevance of phosphatidylserine, long-term studies with larger sample sizes would be required, investigating pure phosphatidylserine preparations at various dosages and in specific cognitive deficits (e.g., executive function, working memory). Additionally, studies would need to directly measure the influence on neuronal plasticity, neurotransmitter systems (e.g., acetylcholine, dopamine), and the ability to cross the blood-brain barrier. Systematic investigations into combination effects with omega-3 fatty acids or phosphatidic acid, as well as comparisons with established therapies (e.g., cognitive training, pharmacotherapy), would be necessary to enable causal attribution of effects. Finally, data on long-term safety and potential interactions with chronic use are lacking.

7. Unresolved Questions

• Blood-brain barrier: It remains unclear whether phosphatidylserine crosses the blood-brain barrier in effective concentrations. Most studies do not measure CNS levels.
• Long-term safety: There are no long-term data on safety and potential interactions, particularly with chronic use.
• Combination effects: The interaction with omega-3 fatty acids or phosphatidic acid has not been systematically investigated. It remains unclear whether synergies or antagonisms exist.