A 12-week randomized, double-blind, placebo-controlled trial in 70 adults aged 35–65 with subjective memory complaints tested 300 mg/day of soybean-derived phosphatidylserine (PS) against placebo. The prespecified primary endpoint — a composite memory score — showed no statistically significant difference between groups at week 12. Exploratory secondary analyses, however, flagged favorable changes in working memory (p = 0.037) and motor speed (p = 0.005), with motor speed effects apparently moderated by participants' blood fatty-acid profiles. PS was well tolerated with no adverse events.
This preprint, not yet peer-reviewed, deserves cautious reading. The trial's most important result is a null finding on the primary endpoint — exactly the rigorous test PS research needs given decades of mixed evidence. The exploratory signals are hypothesis-generating at best; with multiple secondary comparisons, a p-value of 0.037 offers weak protection against false discovery. The sample of 70 is underpowered for subgroup analyses by fatty-acid status. PS has long been marketed for cognitive support, and the FDA's qualified health claim for soy-derived PS and dementia risk dates to 2003 — yet the evidence base in healthy adults remains thin. The fatty-acid moderation angle is biologically plausible (PS absorption may depend on omega-3 status), but it demands a pre-registered, adequately powered replication before influencing supplement decisions. As a confirmatory contribution, this trial is incremental and, on its primary outcome, essentially negative.