Phosphatidylserine (PS)

CognitionCortisolSleep

A phospholipid that makes up cell membranes — especially abundant in the brain. Reduces evening cortisol, supports memory, and is one of the few supplements with an FDA-allowed cognitive claim.

EvidenceStrong

Strong evidence for cognitive support in mild cognitive impairment, age-related memory decline, and ADHD adjunct. Strong for blunting cortisol response to physical / psychological stress. Effects: 4–12 weeks for cognition; days-weeks for cortisol.

Phosphatidylserine is a phospholipid concentrated in neuronal cell membranes. The body makes some, but levels decline with age. Supplementation supports cognitive function (memory, learning, attention) and — uniquely — lowers evening cortisol, which makes it useful for people whose cortisol stays elevated at night and disrupts sleep. The FDA permits a qualified health claim that PS 'may reduce risk of dementia and cognitive dysfunction in the elderly.' Original studies used bovine brain-derived PS; modern supplements use soy- or sunflower-derived (BSE concerns long-since solved).

Form
Soy or sunflower-derived phosphatidylserine. Look for products specifying PS content per serving (300 mg is standard).
Dose
100–300 mg/day for cognitive support. 400–800 mg for cortisol reduction / sleep (split AM/PM, with majority in evening).
Timing
PM for cortisol / sleep effects. AM/PM split for cognitive use.
Schedule
Daily.
Side effects
Generally well-tolerated. GI upset, insomnia (if too high a PM dose), headache.
Interactions
Anticoagulants — mild additive. Anticholinergic medications — opposing action (PS supports acetylcholine).
Contraindications
Soy allergy (use sunflower-derived). Pregnancy / breastfeeding — limited safety data.
Lab markers
Cortisol curve (salivary) for stress tracking. Cognitive testing for MCI / age-related decline.
Food sources
Organ meats (especially brain — limited cultural use), fish, soybeans, white beans, egg yolks. Whole-food intake is modest; supplementation provides therapeutic doses.

Pairs with

Citicoline / Alpha-GPC (cognitive stack). Omega-3 DHA (phospholipid synergy). Magnesium glycinate, ashwagandha (cortisol / sleep stack).