Phosphatidylserine

Most human PS research has concentrated on memory and thinking, traditionally in people with some degree of cognitive decline [3]. A 2024 review described the results for memory as unclear [2]. As of November 11, 2026, we found no meta-analysis or systematic review of phosphatidylserine for memory or cognition in adults without a diagnosed condition (PubMed and Europe PMC search). How each outcome is graded is set out in how we grade evidence, and the evidence matrix compares PS with other compounds.

Does phosphatidylserine improve memory?

Evidence is mixed, and the split follows the source of the PS. The early positive trials used bovine-cortex PS. In a 12-week placebo-controlled trial of 149 adults with age-associated memory impairment, 300 mg a day of bovine-cortex PS (100 mg three times daily) improved scores on learning and memory tasks of daily life compared with placebo [4]. A subgroup analysis suggested that people who scored lowest at the start were most likely to respond [4]. In an industry-affiliated trial (first author at Fidia Research Laboratories), 494 patients aged 65 to 93 with moderate to severe cognitive decline, a clinical population, improved on behavioral and cognitive scales with 300 mg a day of bovine-cortex PS for 6 months compared with placebo [5]. Results may not apply to healthy adults.

The two placebo-controlled trials of soy PS alone found no difference from placebo overall [6][7]. In a randomized trial of 120 adults over 57 with age-associated memory impairment, neither 300 nor 600 mg a day of soy PS for 12 weeks changed any memory, reaction time, planning or attention outcome compared with placebo [6]. In a 6-month double-blind trial run by Yakult researchers using a Yakult soy PS product, 78 Japanese adults aged 50 to 69 with memory complaints, described by the authors as mild cognitive impairment, were randomly assigned to 100 mg, 300 mg or placebo a day [7]. In that trial, test scores rose similarly in every group, including placebo; memory gains against baseline appeared only in people who started with low scores [7]. A 12-week study of 30 older adults with memory complaints by Enzymotec employees reported gains in memory recognition and recall, but it was open-label with no placebo group [8].

Combination products complicate the picture. In a 15-week trial of 157 older adults with memory complaints, funded by Enzymotec according to the safety report from the same trial, PS-DHA improved verbal immediate recall compared with placebo [9][22]. In that Enzymotec-funded trial, further gains in a subgroup with better baseline performance came from a post-hoc analysis, and the authors called the study exploratory [9]. In a Lipogen-funded pilot, PS taken with phosphatidic acid (300 mg PS plus 240 mg phosphatidic acid a day for 3 months) improved memory in 31 elderly people with memory problems, unlike placebo (26 people), in a before-and-after comparison [10]. A 12-month trial enrolled 190 adults with mild cognitive impairment in China, a clinical population; two authors were affiliated with the BYHEALTH Institute of Nutrition & Health [11]. Participants took two capsules a day, each with 31.5 mg PS plus alpha-linolenic acid, ginkgo flavonoids and B vitamins, and improved on some tests compared with placebo [11]. Those effects cannot be assigned to PS alone, and results may not apply to healthy adults.

In 2004, FDA reviewed the studies then available for a qualified health claim and concluded that the credible evidence was very limited and preliminary [24]. It noted that the one study showing no benefit used soy PS, and that there is considerable uncertainty in generalizing results from bovine-cortex PS to soy PS, and vice versa [24]. FDA also said the reliability of the studies it reviewed was limited by flaws in design and analysis [24]. In 2010, EFSA's nutrition panel concluded that a cause and effect relationship could not be established between phosphatidylserine and claimed effects on memory, cognitive function and stress reduction, finding the substance in the claims not sufficiently characterized [30]. For more on the wider topic, see the memory and healthy aging hubs.

Does phosphatidylserine reduce perceived stress?

Evidence is mixed, and the self-rated findings are small and inconsistent. In young adults, 300 mg of PS a day for a month was associated with feeling less stressed and better mood only in those whose neuroticism scores were above the median [12]. In a 3-week trial with four groups of 20, the placebo group showed the expected rise in distress after a standard laboratory stress test (the Trier Social Stress Test), while the group taking 400 mg a day of a PS and phosphatidic acid complex (PAS) showed decreased distress [13]. The abstract reports this emotional effect for the 400 mg dose only [13].

A later trial funded by Lipogen and Lonza enrolled 75 healthy men and gave PAS 200, PAS 400 or placebo for 42 days [14]. This industry-funded trial found no statistically significant effect on the psychological stress response, heart rate or pulse transit time compared with placebo [14]. In a trial funded by Cargill Texturizing Solutions and Giventis, 20 young golfers took 200 mg of PS a day or placebo for 42 days; the drop in perceived stress during tee-off was a trend that did not reach statistical significance (p = 0.07) [17]. See the mood and stress hub for other compounds studied for this outcome.

Stress hormones. Several small trials measured cortisol rather than how people felt. In 9 healthy men, 800 mg a day of bovine-cortex PS for 10 days blunted the ACTH and cortisol response to exercise compared with placebo [16]. In a crossover trial in 10 healthy men, funded by Increnovo with publication paid by Chemi Nutra, mean peak cortisol and cortisol area under the curve around moderate-intensity cycling were 39% and 35% lower after 600 mg a day of PS for 10 days than after placebo [15]. In the Lipogen- and Lonza-funded trial, PAS 400 normalized ACTH and cortisol responses to the stress test in chronically high-stressed men but not in low-stressed men, and PAS 200 had no effect [14]. In the PAS trial with four dose groups, only 400 mg blunted ACTH and cortisol responses; higher doses did not [13]. These are hormone measures, not proof that people feel or function better.

Does phosphatidylserine improve endurance performance?

One small trial reports a benefit. Fourteen active men completed an intermittent cycling test before and after 10 days of 750 mg a day of soy PS or placebo [19]. Time to exhaustion at 85% VO2max rose from 7:51 to 9:51 (min:s) with PS and stayed unchanged with placebo (8:09 to 8:02) [19]. Oxygen uptake kinetics, cortisol, fuel use and feeling states did not change [19]. The authors called it the first study to report improved exercise capacity after PS [19]. As of November 11, 2026, we found no independent replication (PubMed and Europe PMC search).

A companion crossover trial from the same research group in 8 recreationally active men found that 750 mg a day of soy PS did not reduce muscle soreness or markers of muscle damage, inflammation and oxidative stress after prolonged downhill running [20]. A 2006 review by the same lead author describes the overall exercise literature as a small number of studies [3]. Separately, and not counted in this grade, in the industry-funded golf trial the number of good ball flights rose with PS and did not change with placebo [17]. See the physical performance hub.

What the evidence does not show

The memory trials cited here, including one run by Yakult researchers, were in older adults with memory complaints or in clinical groups [3][6][7].

Trials in young, healthy people measured stress hormones, self-rated stress, brain waves or golf and exercise tasks [12][15][16][17][18]. In 16 healthy adults, 42 days of PS lowered one EEG measure (Beta-1 power in a right frontal region) before and after induced stress, compared with placebo [18]. That is a brain-activity signal, not a measured improvement in thinking.

Findings from products that combine PS with omega-3, phosphatidic acid, ginkgo or other ingredients, all from trials funded by or affiliated with ingredient or supplement companies, cannot show what PS alone does [9][10][11].

How oral PS is absorbed and handled by the body has not been fully worked out [3]. In a Lipogen-funded report, serum PS in healthy volunteers peaked 90 minutes after a single dose of PS with phosphatidic acid and returned to baseline after 180 minutes [10]. As of November 11, 2026, we found no other dedicated human pharmacokinetic study of oral PS supplements (PubMed search).

Form matters more than timing for reading this evidence. FDA says soy PS and bovine-cortex PS may not be the same substance because they differ significantly in fatty acid composition [24]. Of the trials cited here, the two placebo-controlled trials of PS alone that found memory or cognitive gains over placebo used the bovine form [4][5] (the second industry-affiliated), and a 2006 review describes soy PS, not bovine, as the preferred source [3]. PS-DHA, a marine-sourced form with omega-3 fatty acids attached that was studied in an Enzymotec-funded trial, is a third distinct preparation [22].

In the trials reviewed here, soy PS was well tolerated. In a randomized, placebo-controlled study of 120 older adults with age-associated memory impairment, blood chemistry, blood counts, blood pressure, heart rate and adverse events did not differ between placebo and 300 or 600 mg a day over 12 weeks [21]. In the Yakult-run 6-month trial, the authors did not observe any side effect caused by soy PS [7]. A 2024 review states that clinical studies have found PS safe and well tolerated [2].

In an Enzymotec-funded trial of PS-DHA in 157 older adults, safety measures did not differ from placebo over 15 weeks; in the open-label extension, people taking PS-DHA for 30 weeks had a reduction in resting diastolic blood pressure and a slight weight gain [22]. An open-label study by Enzymotec employees also reported lower systolic and diastolic blood pressure, which the authors described as unexpected [8]. Bovine-cortex PS was reported as well tolerated in the industry-affiliated 494-patient trial [5], but a 2006 review notes soy PS is preferred because of the possibility of prion infection from brain tissue [3].

Health Canada's natural health product monograph for phosphatidylserine requires no caution, warning, contraindication or known adverse reaction statements on labels [25]. As of November 12, 2026, the NIH Office of Dietary Supplements fact-sheet list (as archived November 1, 2026) has no phosphatidylserine fact sheet, and LiverTox has no phosphatidylserine entry (NCBI Bookshelf search). Memorial Sloan Kettering's About Herbs coverage is not verified as of November 12, 2026 (page not retrievable).

As of November 11, 2026, the sources we checked (a PubMed search and Health Canada's monograph) do not name any medicine that interacts with phosphatidylserine, and we found no human drug-interaction study. Health Canada's monograph requires no caution or warning statements on labels [25]. If you take any medicines, talk to your doctor or pharmacist before combining them with phosphatidylserine.