What is Phosphatidylserine used for?

A phospholipid that is part of cell membranes, including in the brain. Its most persuasive memory trials used a bovine-cortex source in memory-impaired older adults; modern soy- and sunflower-derived PS — what this and every current supplement actually contains — has not cleared that same bar.

What is the studied dose of Phosphatidylserine?

100 mg two to three times daily (≈200–300 mg total) in many studies. A studied dose is what research used, not a recommended dose.

How long does Phosphatidylserine take to work?

Often studied over several weeks of daily use.

What are the side effects of Phosphatidylserine?

Generally well tolerated Occasional GI upset or insomnia at higher doses

Who should avoid Phosphatidylserine?

On blood-thinning medication without clinician review Pregnant or breastfeeding without guidance

Phosphatidylserine Benefits, Dosage, and Side Effects

Full profile

Also known as	PS
Best for	Memory support · Cognitive load and stress
Evidence grade	Grade C — Limited — early or small human trials
Studied dose range	100 mg two to three times daily (≈200–300 mg total) in many studies.
Time to effect	Often studied over several weeks of daily use.
Best form	Soy- or sunflower-derived PS with a stated milligram dose.

Evidence, honestly graded

This is a wrong-source, wrong-population discount. The classic positive trials (Crook 1991, bovine-cortex PS; Kato-Kataoka 2010, soy-PS with a positive result only in a low-baseline subgroup) don't match what a modern label delivers to a healthy adult: a direct RCT of soy-derived PS at both 300 mg and 600 mg/day (Jorissen et al. 2001) failed to beat placebo on the primary cognitive measures in the target population. The FDA's own qualified health claim review for PS and cognitive function/dementia concluded there is "little scientific evidence" supporting the claim. Still a reasonable, well-tolerated inclusion, but the honest grade for soy/sunflower PS in a healthy adult is C, not B.

See the full grading rubric — study type, replication, population match, and dose adequacy — in The Evidence Standard.

Side effects

Generally well tolerated
Occasional GI upset or insomnia at higher doses

Who should avoid it or check first

On blood-thinning medication without clinician review
Pregnant or breastfeeding without guidance

Interactions

May interact with blood thinners and anticholinergic medications — discuss with a clinician

Stacks well with

Citicoline
Bacopa Monnieri

What to look for on a label

Check the elemental PS dose per serving.
Sunflower-derived PS is an option for those avoiding soy.

References

Kato-Kataoka A, Sakai M, Ebina R, et al. (2010). Journal of Clinical Biochemistry and Nutrition, 47(3):246–255Randomized, double-blind, placebo-controlled, n=78 adults 50–69 with memory complaints, 6 monthsStudied dose: 100 mg or 300 mg daily (soy-PS)Delayed verbal recall improved versus placebo in a low-baseline subgroup.
Crook TH, Tinklenberg J, Yesavage J, et al. (1991). Neurology, 41(5):644–649Randomized, double-blind, placebo-controlled, n=149 with age-associated memory impairment, 12 weeksStudied dose: 300 mg daily (bovine-cortex PS)Improved name-face and daily-task memory measures versus placebo.
Jorissen BL, Brouns F, Van Boxtel MP, et al. (2001). Nutritional Neuroscience, 4(2):121–134Randomized, double-blind, placebo-controlled, n=120 adults with age-associated memory impairment, 12 weeksStudied dose: 300 mg or 600 mg daily (soy-PS)No significant improvement over placebo on the primary cognitive measures at either dose.
FDA qualified health claim decision — phosphatidylserine and cognitive function/dementia. FDA's own review of the evidence for a PS/cognition qualified health claim concluded there is "little scientific evidence" supporting it — the basis for grading soy/sunflower PS conservatively rather than trading on the older bovine-PS trials.

Primary citations for some entries above are still being compiled; those without a linked identifier are editorial summaries of the wider literature.

Grades and studied doses are our conservative reading of the human research, shown for education. They are not product claims, and a studied dose is not a recommended dose.

See how Phosphatidylserine compares on grade, dose, and goal in the Evidence Explorer.