Phosphatidylserine: What It Is, Benefits, Side Effects, and Uses

Key Takeaways

• Phosphatidylserine (PS) is a phospholipid (a type of fat molecule) that forms a critical part of every cell membrane in your body, with the highest concentrations in your brain. (1, 2)

• A systematic review and meta-analysis of nine studies (961 participants) found that a phosphatidylserine supplement positively affected memory in older adults with cognitive decline, at doses of 100 to 300 mg per day. (3)

• Phosphatidylserine benefits extend beyond cognition: 600 mg per day blunted cortisol by 35% and increased the testosterone-to-cortisol ratio by 184% following moderate exercise in a placebo-controlled trial. (4)

• Side effects of phosphatidylserine are minimal. It is generally recognized as safe (GRAS) by the FDA when derived from soy or sunflower sources. (1)

• PS levels in the brain decline with age, which is one reason cognitive function deteriorates over time. Supplementation may help offset this decline. (2)

Your brain fog has been getting worse. Names slip away mid-conversation. You feel mentally drained by early afternoon, even after a full night of sleep. If these patterns are becoming more frequent, the issue may be structural, not just behavioral.

What is phosphatidylserine? It is a phospholipid, a type of fat molecule that makes up a critical component of every cell membrane in your body. Your brain contains the highest concentration of PS, where it supports neurotransmitter release, cell-to-cell signaling, and the structural integrity of neurons.  (1, 2) As you age, PS levels in the brain decline, and this decline correlates directly with reduced cognitive function.

This guide covers everything you need to know about phosphatidylserine: how it works, what the clinical evidence shows for memory, stress, and exercise performance, its side effects and safety profile, and how to evaluate a phosphatidylserine supplement.

What Is Phosphatidylserine?

Phosphatidylserine is one of the most abundant phospholipids in the human brain, comprising approximately 15% of the total phospholipid pool in neural tissue.  (2) It is concentrated in the inner leaflet of cell membranes, where it serves multiple functions:

• Cell membrane structure. PS maintains the fluidity and integrity of neuronal membranes, which is essential for cell communication and survival.

• Neurotransmitter release. PS facilitates the release of key neurotransmitters, including acetylcholine (involved in memory and learning), dopamine (motivation and reward), and noradrenaline (alertness and attention). (2, 5)

• Cell signaling. PS acts as a cofactor for enzymes involved in cell communication, including protein kinase C, which plays a role in memory formation.

• Apoptotic signaling. When PS flips to the outer leaflet of the membrane, it signals the immune system to clear damaged or dying cells, a process critical for brain maintenance.

Your body can synthesize small amounts of PS, but the majority comes from dietary sources and supplementation. As you age, the body’s ability to produce and maintain adequate PS levels declines, contributing to the cognitive changes many people experience after 40.  (2)

Phosphatidylserine Benefits: What Does the Research Show?

The benefits of phosphatidylserine are among the most well-documented in the brain health supplement category. Here is what human studies demonstrate:

Memory and Cognitive Function

Kang et al. (2022) conducted a systematic review and meta-analysis of nine studies with 961 participants and concluded that phosphatidylserine supplementation had a positive effect on memory in older adults with cognitive decline, at dosages of 100 to 300 mg per day over periods of 6 weeks to 6 months.  (3)

Glade and Smith (2015) published a comprehensive review in Nutrition that confirmed PS is required for healthy nerve cell membranes and myelin (the protective sheath around nerve fibers), and that aging-related declines in brain PS are associated with impaired neurotransmission and cognitive deterioration.  (2)

Phosphatidylserine benefits for cognition appear to be most pronounced in individuals already experiencing mild cognitive decline, rather than those with healthy baseline function. This makes PS particularly relevant for adults over 40 who notice attention or memory changes. Formulations like BrainZen from Zenos Health include 300 mg of phosphatidylserine, the upper end of the clinically studied range, alongside Cognizin® citicoline for complementary neurotransmitter support.

Cortisol and Stress Response

One of the most distinctive phosphatidylserine benefits is its effect on the stress hormone cortisol. Starks et al. (2008) conducted a double-blind, placebo-controlled, crossover trial in 10 healthy males and found that 600 mg of soy-derived PS per day for 10 days significantly decreased cortisol by 35% and increased the testosterone-to-cortisol ratio by 184% following moderate-intensity exercise.  (4)

Hellhammer et al. (2014) demonstrated that a phosphatidylserine/phosphatidic acid complex (400 mg PS plus 400 mg PA per day) normalized the hyper-responsivity of the HPA axis (the body’s stress response system) in chronically stressed subjects, significantly blunting ACTH and cortisol responses to an acute psychosocial stressor.  (6)

These findings position PS as a dual-function compound: cognitive support and stress modulation. MoodZen from Zenos Health includes 600 mg of phosphatidylserine, the dose used in Stark's cortisol study, within a formulation designed for stress and mood support.

Mood and Emotional Well-Being

Benton et al. (2001) found that 300 mg of PS per day for one month was associated with feeling less stressed and having a better mood in young adults with higher neuroticism scores, the first study to report mood improvement from PS supplementation in a healthy, non-elderly population.  (7)

Exercise Performance and Recovery

Beyond cortisol reduction, PS has been studied for its effects on exercise recovery. By blunting the cortisol response to intense training, PS may help reduce exercise-induced muscle damage and support recovery between sessions.  (4, 5) PS has also been reported to improve well-being and decrease perceived muscle soreness in athletes involved in cycling, weight training, and endurance running.

Where Does Phosphatidylserine Come From?

Your body produces small amounts of PS, but dietary and supplemental sources are important for maintaining optimal levels.

Food sources. PS is found in organ meats (brain, liver, kidney), soybeans, white beans, egg yolks, and dairy products. However, the amounts in typical dietary servings are far below the 100 to 600 mg per day used in clinical studies.

Supplement sources. Early PS research used bovine-cortex (brain-derived) PS, but due to concerns about prion contamination (the same issue behind mad cow disease), modern phosphatidylserine supplements are derived from soy lecithin or sunflower lecithin.  (5) Both soy-derived and sunflower-derived PS are recognized as safe (GRAS) by the FDA.  (1)

Side Effects of Phosphatidylserine

The side effects of phosphatidylserine are minimal in clinical studies. PS has a strong safety profile at the doses used in human trials (100 to 800 mg per day). However, some individuals may experience:

• Mild gastrointestinal discomfort. Nausea or stomach upset, typically at higher doses. This usually resolves with food.

• Insomnia. Some individuals report difficulty sleeping at higher doses, particularly when PS is taken later in the day. Taking PS in the morning or early afternoon may help.

• Potential blood-thinning interaction. PS may enhance the effect of anticoagulant medications (blood thinners). If you take warfarin, heparin, or similar medications, consult your healthcare provider before supplementing. (1)

No serious adverse events have been reported in clinical trials at recommended dosages.  (1, 3) The FDA’s GRAS designation for soy-derived and sunflower-derived PS reflects this favorable safety profile.

Clinical Note: If you are pregnant, nursing, or taking medications for depression, blood pressure, or blood clotting, consult your healthcare provider before starting any phosphatidylserine supplement.

How Much Phosphatidylserine Should You Take?

The optimal dose of a phosphatidylserine supplement depends on your primary goal:

• For cognitive support and memory: 100 to 300 mg per day. The systematic review found this range effective for memory improvement in older adults with cognitive decline. (3) BrainZen provides 300 mg.

• For cortisol modulation and stress: 400 to 600 mg per day. The cortisol-blunting effect appears dose-dependent, with 600 mg per day producing the most consistent results for exercise-induced cortisol reduction. (4, 6) MoodZen provides 600 mg.

• For mood support, 300 mg per day showed mood benefits in young adults in the Benton et al. study. (7)

PS is fat-soluble, so absorption improves when taken with a meal containing dietary fat. Most clinical trials administered PS in divided doses (two to three times daily), though single daily doses have also been used effectively.

What to Look for in a Phosphatidylserine Supplement

Not all phosphatidylserine supplements are equivalent. Key factors to evaluate:

• Source. Soy-derived or sunflower-derived PS is the modern standard. Avoid bovine-cortex PS. (5)

• Dose per serving. Many products contain only 100 mg per serving, which is the minimum studied dose. For stress and cortisol modulation, you may need 400 to 600 mg per day.

• Complementary ingredients. PS works through the membrane support. Combining it with compounds that address other cognitive pathways (neurotransmitter synthesis, cerebral blood flow, mitochondrial energy) provides a more comprehensive approach.

• Third-party testing. Independent verification ensures the PS content matches the label claim and is free from contaminants.

Phosphatidylserine in Zenos Health Formulations

Zenos Health includes phosphatidylserine at clinically relevant doses in two formulations, each designed for a different primary application:

BrainZen (300 mg phosphatidylserine): Cognitive Optimization

BrainZen pairs 300 mg of PS with:

• Cognizin® citicoline (250 mg) for acetylcholine synthesis and neuronal membrane support

• Nicotinamide Riboside (1000 mg) for mitochondrial energy in neurons

• Nattokinase NSK-SD® (100 mg) for cerebral blood flow

• CogniUp® (100 mg) for neuroprotection

• FloraGlo® Lutein (50 mg) for macular blue-light defense

MoodZen (600 mg phosphatidylserine): Stress and Mood Support

MoodZen pairs 600 mg of PS (the cortisol study dose) with:

• SaraPepp Nu® (300 mg) for well-being and natural anxiolytic support

• Lion’s Mane (300 mg) for nerve growth factor (NGF) production

• Cognizin® citicoline (250 mg) for cognitive clarity under stress

• Saffron Extract (100 mg) for mood and emotional balance

• Alpinia galanga (200 mg) for cognitive support

Browse the Brain Health collection for cognitive support, or explore the full product range at Zenos Health.

Frequently Asked Questions