Phosphatidylserine in Ireland: Benefits, Cortisol Evidence, Dosage and Side Effects
Phosphatidylserine (PS) is one of the few supplements with real, if modest, human trial data behind both a cognitive angle and a stress/cortisol angle. This guide separates what the trials actually measured from what marketing copy implies — and explains why it isn't the same thing as sunflower or soy lecithin.
Phosphatidylserine (PS) is a phospholipid concentrated in brain cell membranes, sold in Ireland as a food supplement regulated by the FSAI — it is not a medicine and carries no EU-authorised health claim under Regulation (EC) No 1924/2006. The strongest human evidence signals are a six-month memory trial in elderly adults (Kato-Kataoka et al. 2010, PMID 21103034) and small-to-moderate trials showing PS is proposed to modulate cortisol reactivity under stress (Hellhammer et al. 2014, PMID 25081826; Starks et al. 2008, PMID 18662395). What is not proven in humans: a general "reduces stress" or "improves memory" effect in healthy adults outside these specific trial conditions — EFSA concluded in 2010 that a cause-and-effect relationship could not be established. Swanson Phosphatidylserine 100mg (30 softgels, €18.90 inc. VAT) is available from Probiotic.ie with nationwide Ireland delivery.
Phosphatidylserine (PS) definition: Phosphatidylserine is a phospholipid found in the inner layer of cell membranes throughout the body, most densely in brain and nerve tissue, and commercially produced today from soy or sunflower lecithin rather than the bovine brain cortex source used in early research.
A phosphatidylserine supplement is a concentrated soy- or sunflower-derived phospholipid extract, sold as a softgel food supplement — not a medicine. Human trials link it to modest memory-retention effects in older adults with memory complaints and to changes in cortisol reactivity under acute stress or exercise. Evidence is real but limited: trial sizes are small (n=8 to n=78), and EFSA has not authorised a cognitive or stress-related health claim. Swanson Phosphatidylserine 100mg (30 softgels, €18.90) ships nationwide from Dublin.
- What it is: A phospholipid concentrated in brain and nerve cell membranes
- Where found in the body: Inner membrane layer of cells, most densely in the brain
- Dietary sources: Trace amounts in organ meats, soy, and white beans; supplements use concentrated soy or sunflower extracts
- Supplement source: Soy-derived (most brands, incl. Swanson) or sunflower-derived — not vegetarian in gelatin softgel form
- EU health claim status: No EU-authorised health claim (EFSA, 2010, EFSA Journal 8(10):1749)
- Typical trial dose: 100–600mg/day depending on study endpoint
- Is it a stimulant or medicine? No. It is a food supplement, not classified as a stimulant or medicine
- Vegetarian/vegan suitable? No — Swanson's softgel uses gelatin
- Irish regulatory status: Food supplement under FSAI guidelines — not a medicine
- Irish VAT rate on supplements: 13.5%
- Phosphatidylserine is not a medicine and is not licensed to treat, cure or prevent any disease, including dementia or Alzheimer's disease
- It is not the same molecule as phosphatidylcholine, the dominant phospholipid in whole soy or sunflower lecithin
- It is not proven to "reduce stress" or "improve memory" in healthy adults outside the specific trial populations and doses studied
- A sunflower lecithin softgel is not an equivalent substitute for a concentrated phosphatidylserine supplement
- It is not made from bovine brain cortex today — that source was discontinued after BSE safety concerns in the 1990s
What is well-supported: Small-to-moderate human trials link soy-derived PS to changes in memory retention (Kato-Kataoka et al. 2010, n=78, 6 months) and cortisol/ACTH reactivity under stress (Hellhammer et al. 2014, n=75, 42 days; Starks et al. 2008, n=10, 10 days).
What is not proven: A general cognitive-enhancement or stress-reduction effect in healthy adults. EFSA concluded in 2010 that cause-and-effect could not be established across the submitted evidence.
Most relevant human dose range: 100–600mg/day, depending on whether the endpoint studied was memory (lower end, longer duration) or acute cortisol response (higher end, shorter duration).
Key safety note: Generally well tolerated per Jorissen et al. (2002); speak to a GP or pharmacist before use if you take anticoagulant medication or have a soy allergy.
| Feature | Specification | Evidence Level |
|---|---|---|
| Memory retention (elderly, memory complaints) | 100–300mg/day, 6 months | Partial — single RCT, PMID 21103034 |
| Cortisol/HPA-axis reactivity (chronic stress) | 400mg/day, 42 days | Partial — single RCT, PMID 25081826 |
| Acute exercise cortisol response | 600mg/day, 10 days | Limited — small n=10 trial, PMID 18662395 |
| General "stress reduction" claim | — | No EU-authorised claim (EFSA 2010) |
| Sleep quality outcome | — | No direct trial data identified |
| Irish regulatory status | FSAI food supplement, 13.5% VAT | Confirmed — not a medicine |
- What Is Phosphatidylserine?
- Phosphatidylserine and Cortisol: What the Evidence Shows
- Phosphatidylserine and Memory
- Benefits and Side Effects
- Dosage: How Much and When
- Phosphatidylserine vs Phosphatidylcholine
- Safety, Interactions and Who Should Avoid It
- Sleep and Anxiety: What We Actually Know
- Phosphatidylserine in Ireland: Regulation and Where to Buy
The Basics
What Is Phosphatidylserine?
Phosphatidylserine is a phospholipid — a fat-based structural molecule — concentrated in the inner layer of cell membranes, most densely in brain and nerve tissue.1 The body synthesises PS itself from other phospholipids, and small amounts are also present in the diet, mainly in organ meats and some legumes.
Early PS research in the 1980s and 1990s, including the Monteleone et al. studies discussed below, used PS extracted from bovine (cattle) brain cortex.2 That source was discontinued industry-wide after BSE ("mad cow disease") safety concerns, and manufacturers moved to plant-based extraction — primarily soy lecithin, with sunflower lecithin as a soy-free alternative.1 EFSA has specifically noted that bovine-derived and soy-derived PS are distinct substances, and evidence from one source cannot be assumed to apply to the other.6
Stress Physiology
Phosphatidylserine and Cortisol: What the Evidence Shows
This is the most searched angle for phosphatidylserine after basic product queries, and it has genuine — if limited — human trial support. Monteleone et al. (Neuroendocrinology, 1990, PMID 2170852) gave 8 healthy men either 50mg or 75mg of bovine cortex-derived PS before a bicycle ergometer stress test and found both doses significantly blunted the ACTH and cortisol response to physical stress, without affecting catecholamine or glucose responses.2 This trial used the now-discontinued bovine source, at a single acute dose — it does not directly validate today's soy-derived products at trial-length dosing.
Starks et al. (J Int Soc Sports Nutr, 2008, PMID 18662395) gave 10 healthy men 600mg/day of soy-derived PS for 10 days before moderate-intensity exercise, and recorded a 39% reduction in peak cortisol and a 35% reduction in cortisol area-under-curve versus placebo (both p<0.05), alongside a 184% increase in the testosterone-to-cortisol ratio.3 The sample size (n=10) is small — a genuine limitation, not a footnote.
The largest and most recent trial, Hellhammer et al. (Lipids Health Dis, 2014, PMID 25081826), gave 75 healthy but chronically stressed men either 200mg or 400mg/day of a soy-based PS/phosphatidic acid complex for 42 days. In the subgroup with the highest baseline stress, the 400mg dose significantly normalised ACTH (p=0.010), salivary cortisol (p=0.043) and serum cortisol (p=0.035) responses versus placebo; the 200mg dose showed no significant difference from placebo.4
These trials measured cortisol reactivity under defined stress or exercise conditions in specific, small populations. They do not establish that phosphatidylserine "reduces stress" in general, and EFSA has not authorised a stress-related health claim for PS.
The clinical and mechanistic research discussed in this article relates to phosphatidylserine as a studied compound. It should not be read as a claim that Swanson Phosphatidylserine produces these effects. This product is a food supplement, not a medicine. No authorised EU health claim is currently made for phosphatidylserine on this page or on the product.
Swanson Phosphatidylserine 100mg
Soy-derived PS (Sharp-PS complex), 30 softgels, dispatched from Dublin.
€18.90 inc. 13.5% Irish VAT · Nationwide Ireland delivery · Swanson stocked by Probiotic.ie
Cognitive Research
Phosphatidylserine and Memory
The best-supported human trial on PS and cognition is Kato-Kataoka et al. (J Clin Biochem Nutr, 2010, PMID 21103034), a 6-month trial in 78 elderly Japanese adults with memory complaints, comparing 100mg and 300mg/day of soy-derived PS to placebo. Among participants with lower baseline memory scores, delayed verbal recall — a memory function attenuated in the earliest stages of dementia — improved significantly versus baseline in the PS groups, while the placebo group's scores did not change.1
Not every trial in this space has been positive. A review by the Alzheimer's Drug Discovery Foundation's Cognitive Vitality programme notes that other randomised trials found soy-derived PS at 300mg or 600mg/day had no measurable effect over 12 weeks, and that a separate trial combining DHA with soy-derived PS failed to influence cognition or blood-flow measures in healthy 50–70 year olds with subjective memory complaints.7 The same review flags that most PS trials are small, poorly powered, and that no meta-analysis currently exists to pool results reliably.
n=78, 100mg or 300mg/day soy-derived PS, 6 months. Delayed verbal recall improved significantly vs baseline in PS groups with lower starting scores; placebo group unchanged.
n=75 chronically stressed men, 400mg/day soy-based PS/PA complex, 42 days. ACTH (p=0.010), salivary cortisol (p=0.043) and serum cortisol (p=0.035) responses significantly normalised vs placebo in the high-stress subgroup.
n=10 healthy men, 600mg/day soy-derived PS, 10 days. Peak cortisol reduced 39% and cortisol AUC reduced 35% vs placebo (p<0.05). Sample size is small; result needs replication in a larger cohort before it can be treated as established.
Per the Alzheimer's Drug Discovery Foundation's Cognitive Vitality review, other RCTs of soy-derived PS at 300–600mg/day found no measurable cognitive effect over 12 weeks, and a DHA + PS-soy combination trial found no effect on cognition or cerebral blood flow in healthy adults aged 50–70 with subjective memory complaints. Evidence for a general cognitive-enhancement effect is mixed, not settled.
EFSA's 2010 review of five separate PS health claim submissions concluded that a cause-and-effect relationship between phosphatidylserine consumption and cognitive function, memory, mental performance or stress reduction could not be established from the evidence provided. No EU-authorised health claim currently exists for PS as a result.
Benefits and Side Effects
Phosphatidylserine Benefits and Side Effects
Based on the trials above, the two areas with genuine (if limited) human evidence are memory retention in older adults with existing memory complaints, and cortisol/HPA-axis reactivity under acute stress or exercise. Outside those specific conditions, claims of broader "brain-boosting" or "stress-relief" benefits go beyond what the cited trials measured.
On safety, Jorissen et al. (Nutr Neurosci, 2002, PMID 12385596) assessed soy-derived PS at 200mg three times daily (600mg/day total) in elderly participants and found it well tolerated, with mild gastrointestinal upset the most commonly reported issue and no serious adverse events.5 As with any soy-derived product, those with a soy allergy should avoid it — Swanson's label carries both a soy allergen declaration and a bioengineered (GM) food ingredient disclosure.
Dosing
Phosphatidylserine Dosage: How Much and When
There is no single official dose because trials have used different amounts for different endpoints. Memory-focused trials used lower doses over longer periods — 100–300mg/day for 6 months (Kato-Kataoka et al. 2010). Cortisol- and stress-focused trials used higher doses over shorter periods — 200–600mg/day for 10 to 42 days (Hellhammer et al. 2014; Starks et al. 2008).
Swanson Phosphatidylserine softgels are 100mg each, with a suggested use of 1–3 softgels daily (100–300mg), which sits within the published trial range. This is general dosing information based on published research, not a personalised recommendation — check the product label and consult a pharmacist or GP if you are on medication or have a health condition.
Comparison
Phosphatidylserine vs Phosphatidylcholine
This is a real, searched comparison — and it matters because it explains why a sunflower lecithin softgel is not the same thing as a phosphatidylserine supplement. Both are phospholipids, and both are found together in whole lecithin, but they are structurally different molecules studied for different reasons. Phosphatidylcholine is the dominant phospholipid in whole soy or sunflower lecithin; phosphatidylserine is a minor component — soy lecithin is roughly 3% phosphatidylserine by total phospholipid content.1 Supplements sold specifically as "phosphatidylserine" use a concentrated, enriched extract — not whole lecithin — to reach the 100–600mg doses used in the trials above.
Probiotic.ie stocks both, and search behaviour on the site shows customers looking at phosphatidylserine also view Sunflower Lecithin — worth clarifying the two products serve different purposes rather than treating one as a substitute for the other.
| Feature | Swanson Phosphatidylserine | NOW Foods Sunflower Lecithin |
|---|---|---|
| Dominant phospholipid | Phosphatidylserine (concentrated) | Phosphatidylcholine (majority of lecithin) |
| Source | Soy (Sharp-PS complex) | Sunflower seeds |
| Soy-free? | No — contains soy | Yes |
| Dose per softgel | 100mg | 1,200mg (whole lecithin, not isolated PS) |
| Studied for | Memory retention, cortisol reactivity | Choline supply, fat emulsification |
| Price | €18.90 / 30 softgels | €29.95 / 200 softgels |
| Vegetarian suitable | No (gelatin softgel) | No (bovine gelatin softgel) |
If you specifically want the phosphatidylserine dose used in the memory and cortisol trials above, a concentrated PS product is the relevant one — whole lecithin won't get you there at a comparable dose. If you have a soy allergy or want a general phospholipid/choline source rather than isolated PS, sunflower lecithin is the soy-free option.
Safety
Is Phosphatidylserine Safe? Interactions and Who Should Avoid It
Jorissen et al. (2002, PMID 12385596) found soy-derived PS well tolerated at 600mg/day in elderly participants over the study period, with no serious adverse events reported.5 As a general precaution for any supplement that may influence endocrine or neurological signalling, speak to a GP or pharmacist before starting phosphatidylserine if you are taking anticoagulant medication, are pregnant or breastfeeding, have a soy allergy, or are managing an existing medical condition.
Honest Evidence Check
Phosphatidylserine and Sleep or Anxiety: What We Actually Know
"Phosphatidylserine sleep" and "phosphatidylserine anxiety" are both real search terms, so it's worth being direct: none of the trials reviewed for this guide measured sleep quality or used a validated anxiety scale as a primary outcome. The link some sources draw is indirect — evening cortisol elevation is associated with poorer sleep in general stress physiology, and PS has shown cortisol-modulating effects in the specific trials above. That is a plausible hypothesis, not a demonstrated result, and it should be read as exactly that.
Sleep and anxiety outcomes have not been directly tested for phosphatidylserine in the trials reviewed here. This product is a food supplement, not a medicine, and no sleep- or anxiety-related claim is made for it.
Swanson Phosphatidylserine 100mg
Soy-derived PS (Sharp-PS complex), 30 softgels, dispatched from Dublin.
€18.90 inc. 13.5% Irish VAT · Nationwide Ireland delivery · Swanson stocked by Probiotic.ie
Ireland
Phosphatidylserine in Ireland: Regulation and Where to Buy
Phosphatidylserine is legal to buy and sell in Ireland as a food supplement. It falls under the Food Safety Authority of Ireland's (FSAI) food supplement guidelines, not medicines regulation, and Irish VAT of 13.5% applies.8 No EU-authorised health claim currently exists for phosphatidylserine under Regulation (EC) No 1924/2006, following EFSA's 2010 review — so compliant Irish retailers, including Probiotic.ie, describe the compound and its research without making disease-treatment or guaranteed-benefit claims.
Product details on this page — including dose (100mg per softgel), capsule count (30), source (soy-derived Sharp-PS complex), and price (€18.90 inc. VAT at 13.5%) — were verified by Probiotic.ie from the current Swanson product listing. Product details should always be checked against the current label before use, as formulations and pricing may change.
- Phosphatidylserine is a phospholipid concentrated in brain and nerve cell membranes, sold in Ireland as a soy- or sunflower-derived food supplement.
- Phosphatidylserine is not the same molecule as phosphatidylcholine, the dominant phospholipid in whole lecithin.
- EFSA concluded in 2010 that a cause-and-effect relationship between PS and cognitive function or stress reduction could not be established (EFSA Journal, 2010;8(10):1749).
- Human trials use 100–600mg/day depending on endpoint. Evidence for memory and cortisol effects is real but limited to specific small trials.
- The strongest human evidence signal is a six-month memory-retention improvement in elderly adults with memory complaints (Kato-Kataoka et al., J Clin Biochem Nutr, 2010, PMID 21103034).
- Soy lecithin naturally contains roughly 3% phosphatidylserine by phospholipid content — whole lecithin is not a substitute for a concentrated PS supplement.
- Modern PS supplements are soy- or sunflower-derived, not bovine brain cortex-derived — that source was discontinued for BSE safety reasons.
- No direct human trial data exists for phosphatidylserine and sleep quality or anxiety scales — any link is inferred from cortisol research, not demonstrated directly.
- In Ireland, phosphatidylserine supplements are regulated by the FSAI as food supplements — not medicines. 13.5% VAT applies.
- Swanson Phosphatidylserine 100mg (30 softgels, €18.90) is available from Probiotic.ie with nationwide Ireland delivery from Dublin.
This guide was prepared by Probiotic.ie using the following process:
- Reviewed the primary clinical sources: Kato-Kataoka et al. 2010, Hellhammer et al. 2014, Starks et al. 2008, Monteleone et al. 1990, and the Jorissen et al. 2002 safety trial, cross-referenced against PubMed listings and open-access mirrors.
- Reviewed EFSA's 2010 Article 13(1) opinion on phosphatidylserine health claims directly.
- Separated cognitive/stress research context from any product-specific claim throughout.
- Checked FSAI food-supplement rules for Irish compliance and confirmed no EU-authorised health claim exists for PS.
- Verified Swanson Phosphatidylserine and NOW Foods Sunflower Lecithin product details (dose, source, price) against the live Probiotic.ie listings.
- Made no disease-treatment claims for either product.
Frequently Asked Questions
What is phosphatidylserine?
Phosphatidylserine (PS) is a phospholipid concentrated in the inner layer of cell membranes, particularly in brain tissue. The body synthesises some PS itself; the rest comes from dietary sources or supplements. Modern supplements are typically made from soy lecithin or sunflower lecithin rather than the bovine brain cortex source used in early research, which was discontinued after BSE ("mad cow disease") safety concerns in the 1990s.
Does phosphatidylserine lower cortisol?
Human trials suggest phosphatidylserine is proposed to modulate the hypothalamic-pituitary-adrenal (HPA) axis stress response. Starks et al. (2008, PMID 18662395) recorded a 39% reduction in peak cortisol after exercise in 10 men taking 600mg/day for 10 days. Hellhammer et al. (2014, PMID 25081826) found a 400mg/day soy-based PS complex significantly normalised ACTH (p=0.010) and cortisol responses (p=0.035) versus placebo, but only in the highest-stress subgroup of 75 chronically stressed men over 42 days; the 200mg dose showed no significant effect. Both trials are small to moderate in size; EFSA has not authorised a stress-related health claim for PS.
What is the correct phosphatidylserine dosage?
Human trials have used doses from 100mg to 600mg per day. Memory-focused trials, including Kato-Kataoka et al. (2010, PMID 21103034), used 100–300mg/day over six months. Stress and cortisol trials used 200–600mg/day over 10–42 days. Swanson Phosphatidylserine softgels (100mg each) suggest 1–3 softgels daily, in line with published trial ranges. This is general dosing information, not a personalised recommendation.
What are the benefits and side effects of phosphatidylserine?
Human research on phosphatidylserine has focused mainly on memory retention in older adults with memory complaints and on HPA-axis (cortisol) reactivity under stress or exercise. Jorissen et al. (2002, PMID 12385596) found soy-derived PS at 200mg three times daily (600mg/day) was well tolerated in elderly participants, with mild gastrointestinal upset the most commonly reported issue. No EU-authorised health claim currently exists for phosphatidylserine under Regulation (EC) No 1924/2006.
Does phosphatidylserine help with sleep or anxiety?
Direct human trial evidence on phosphatidylserine for sleep or anxiety outcomes is limited. The rationale is indirect: PS has been studied for HPA-axis and cortisol reactivity, and elevated evening cortisol is associated with poorer sleep in general stress physiology research. This is a plausible mechanism, not a demonstrated outcome — no phosphatidylserine trial in this data set measured sleep quality or a validated anxiety scale as a primary endpoint.
What is the difference between phosphatidylserine and phosphatidylcholine?
Both are phospholipids found in lecithin, but they are different molecules studied for different reasons. Phosphatidylserine is concentrated for cognitive and stress-response research. Phosphatidylcholine is the dominant phospholipid in whole soy or sunflower lecithin (soy lecithin is roughly 3% phosphatidylserine by phospholipid content) and is more associated with choline supply, fat emulsification, and everyday cooking or supplement use. A sunflower lecithin softgel is not a substitute for a concentrated phosphatidylserine supplement — the PS content in whole lecithin is a small fraction of the total phospholipid mix.
Is phosphatidylserine made from soy or sunflower?
Both soy and sunflower can be used as source material for phosphatidylserine extraction, alongside the historical bovine brain cortex source, which was discontinued for safety reasons. Most PS supplements on the market today, including Swanson Phosphatidylserine, use a soy-derived complex (Sharp-PS). Soy-derived PS carries a soy allergen declaration and, on some brands, a bioengineered (GM) food ingredient disclosure — check the label if you have a soy allergy or GM-ingredient preference.
Is phosphatidylserine safe? Does it interact with medication?
Jorissen et al. (2002, PMID 12385596) reported soy-derived phosphatidylserine was well tolerated in elderly participants at 600mg/day, with no serious adverse events. As with most supplements affecting endocrine or neurological pathways, anyone on anticoagulant medication, with a soy allergy, who is pregnant or breastfeeding, or managing a medical condition should speak to a GP or pharmacist before starting phosphatidylserine. This is general safety information, not personalised medical advice.
Is phosphatidylserine legal in Ireland?
Yes. Phosphatidylserine is legal to sell and purchase in Ireland as a food supplement, regulated by the Food Safety Authority of Ireland (FSAI) under food supplement guidelines. It is not a medicine, and no EU-authorised health claim currently exists for phosphatidylserine under Regulation (EC) No 1924/2006. Irish VAT of 13.5% applies to food supplements.
Where can I buy phosphatidylserine in Ireland?
Swanson Phosphatidylserine 100mg (30 softgels, €18.90 inc. VAT) is available from Probiotic.ie with nationwide Ireland delivery, dispatched from Dublin. Probiotic.ie is an Irish retailer stocking Swanson supplements.
Sources
- Kato-Kataoka A, Sakai M, Ebina R, Nonaka C, Asano T, Miyamori T. Soybean-Derived Phosphatidylserine Improves Memory Function of the Elderly Japanese Subjects with Memory Complaints. J Clin Biochem Nutr. 2010;47(3):246-255. PMID 21103034. DOI: 10.3164/jcbn.10-62. — PubMed
- Monteleone P, Beinat L, Tanzillo C, Maj M, Kemali D. Effects of Phosphatidylserine on the Neuroendocrine Response to Physical Stress in Humans. Neuroendocrinology. 1990;52(3):243-248. PMID 2170852. — PubMed
- Starks MA, Starks SL, Kingsley M, Purpura M, Jäger R. The effects of phosphatidylserine on endocrine response to moderate intensity exercise. J Int Soc Sports Nutr. 2008;5:11. PMID 18662395. — PubMed
- Hellhammer J, Vogt D, Franz N, Freitas U, Rutenberg D. A soy-based phosphatidylserine/phosphatidic acid complex (PAS) normalizes the stress reactivity of the hypothalamus-pituitary-adrenal axis in chronically stressed male subjects: a randomized, placebo-controlled study. Lipids Health Dis. 2014;13:121. PMID 25081826. — PubMed
- Jorissen BL, Brouns F, Van Boxtel MP, Ponds RW, Verhey FR, Jolles J, Riedel WJ. Safety of soy-derived phosphatidylserine in elderly people. Nutr Neurosci. 2002;5(5):337-343. PMID 12385596. — PubMed
- EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). Scientific Opinion on the substantiation of health claims related to phosphatidyl serine (ID 552, 711, 734, 1632, 1927) pursuant to Article 13(1) of Regulation (EC) No 1924/2006. EFSA Journal. 2010;8(10):1749. — EFSA
- Alzheimer's Drug Discovery Foundation. Cognitive Vitality: Phosphatidylserine (research review). — ADDF
- Food Safety Authority of Ireland. Food Supplements Legislation. — FSAI