Phosphatidylserine: Benefits, Dosage and the Evidence Gap
By Peter Benson, Cognitive Enhancement Researcher · Updated October 2026 · Citations re-verified
Short answer: Phosphatidylserine is a fat found in brain cell membranes. Its reputation rests on trials from the early 1990s that used PS from cow brains, which is no longer sold. Trials of the soy-derived PS you can buy are mixed: one found no effect, and a smaller one found memory gains only in people with lower starting scores.
⚕️ Educational information, not medical advice — full disclaimer. This page contains one affiliate link, in the buying section.
Phosphatidylserine (PS) is often called the best-evidenced nootropic, and it is the only one with an FDA qualified health claim for cognition. Both statements need context. The strong trials used a form of PS nobody sells any more, and the FDA claim comes with the agency’s own warning that the evidence is weak.
This guide covers what PS is, what the trials found and with which form, what the FDA claim means, dosing, cautions, and my own use. For the wider picture, see the Nootropics & Supplements guide.
What phosphatidylserine is
PS is a phospholipid, one of the fats that form cell membranes. It is concentrated on the inner side of nerve cell membranes, where it helps with signalling and with the release of chemical messengers (Glade & Smith, 2015). Brain PS levels tend to fall with age, and the theory behind supplementing is that restoring it supports membrane function. That is plausible, but it hasn’t been shown directly in people.
PS is sometimes sold as a partner for a choline source such as alpha-GPC. That pairing is a theory; no trial has tested the combination.
The phosphatidylserine trials, and which PS they used
Bovine PS: the landmark trials. In the best-known trial, 149 adults aged 50 to 75 with age-associated memory impairment took 300mg of PS a day or placebo for 12 weeks. The PS group improved on several memory tasks, most clearly those with the lowest starting scores (Crook et al., 1991). A six-month multicentre trial in 494 older adults with cognitive decline also found benefits on cognitive and behavioural measures (Cenacchi et al., 1993). Both used PS extracted from cow brains.
Bovine-brain PS was withdrawn in the 1990s over the theoretical risk of transmitting mad cow disease. Manufacturers switched to PS made from soy or sunflower lecithin, which has a different fatty-acid make-up. So the trials behind PS’s reputation tested a product you cannot buy.
Soy PS: the form sold today. The evidence is mixed. In a 12-week trial of 120 older adults with age-associated memory impairment, 300mg or 600mg a day of soy PS made no difference to memory or any other cognitive measure (Jorissen et al., 2001). In a six-month Japanese trial of 78 adults aged 50 to 69 with memory complaints, scores rose in all groups, including placebo, with no clear overall advantage for PS; only in a subgroup who started with lower scores did memory, mostly delayed word recall, improve more with 100mg or 300mg of soy PS than with placebo (Kato-Kataoka et al., 2010). Subgroup findings like this need confirming. A pilot study of 30 older adults on 300mg for 12 weeks reported memory improvements, but it had no placebo group, so it can’t separate the supplement from practice and expectation (Richter et al., 2013).
Stress hormones. In a small study of nine healthy men, 800mg a day of PS blunted the rise in cortisol and ACTH after hard exercise; 400mg did not (Monteleone et al., 1992). Later sports studies used similar high doses. This is a real but small finding, at well above the cognitive dose, and it hasn’t been shown to improve thinking under stress.
What the FDA qualified health claim means
In 2003 the FDA allowed supplement makers to say that PS “may reduce the risk of dementia” and “cognitive dysfunction in the elderly”, but only alongside the agency’s own wording that the research is “very limited and preliminary” and that “FDA concludes that there is little scientific evidence supporting this claim.” A qualified claim exists because the evidence was too weak for a standard one. It is not an endorsement.
Phosphatidylserine benefits ranked by evidence
🟢 Stronger or replicated evidence · 🟡 Limited, mixed or preliminary evidence · 🔴 Not established or not supported
Phosphatidylserine dosage
Who has the best case to try it
Older adults with mild memory complaints match the trials, and the one positive placebo-controlled soy trial found gains only in people who started with lower scores. New or worsening memory problems deserve a medical check first. See Memory & Learning.
Healthy younger adults have little direct evidence. Try it only with low expectations and a plan to stop if nothing changes.
Worked example — a fair 12-week test
Before starting. Choose one concrete measure, such as recalling a 15-word list after 20 minutes. Run it twice a week for two weeks to see your normal range.
Weeks 1–12. PS with food every day, nothing else new. Keep testing twice a week with different word lists.
Judging it. If your scores stay inside your starting range, stop: an inert daily supplement still costs money. If they rise clearly above it, treat that cautiously. Practice, sleep, motivation and expectation can all move the scores, and a drop after stopping doesn’t prove PS was responsible either.
What this can and can’t tell you. An unblinded test like this helps you decide whether the spending feels worthwhile. It can’t establish cause; only a placebo-controlled comparison can do that.
The NeuroEdge Formula Phosphatidylserine Self-Testing Framework
A cautious way to try PS and decide whether to keep it. Not a prescription.
1. Check medicines first
If you take blood thinners, check with your pharmacist or doctor before starting.
2. Buy the right form
Soy or sunflower PS with the PS content in mg. Never bovine.
3. Measure something real
A repeatable memory task, tested before and during, with nothing else new.
4. Decide at a set point
After about 12 weeks, stop if nothing has moved. A change is a reason to keep watching, not proof that PS caused it.
Peter’s Testing Notes
A personal impression, not tracked data
What I take. I started Jarrow Formulas PS 100, a soy-derived 100mg softgel, in 2020. For the first years I took 300mg a day, one softgel with each of three meals. I now eat one meal a day, so I take 200mg with that meal. I’ve stayed on it since.
What I noticed. Nothing I can point to: no change in memory and no difference on stressful days that I could separate from everything else. I knew what I was taking the whole time, and I never tested it against a baseline.
An earlier version of these notes quoted percentage improvements from an online cognitive test and described steadier recall and less stress-driven fog. None of that was accurate, and it has been removed.
Buying phosphatidylserine
Look for soy- or sunflower-derived PS (sunflower suits people avoiding soy), the PS content stated in mg per capsule, third-party testing, and softgels or capsules sized so the dose is easy to hit. Avoid any product listing bovine brain.
Jarrow Formulas PS 100 — soy-derived, 100mg per softgel
Clear PS content per softgel, so three a day matches the 300mg trial dose. It is what I take. No trial has tested this product, and soy PS has weaker evidence than the bovine PS in the landmark trials.
This is an affiliate link. If you buy through it, NeuroEdge Formula may earn a commission at no extra cost to you.
Cautions and interactions
Blood thinners. There is little clinical evidence that PS increases bleeding or interacts with anticoagulants, but it hasn’t been properly studied. If you take warfarin, another anticoagulant or an antiplatelet medicine such as aspirin, check with your pharmacist or doctor before using it.
Side effects. PS is generally well tolerated in trials of up to six months. Mild stomach upset is the most common complaint and usually settles when taken with food.
Pregnancy and breastfeeding. Not recommended, because there is too little safety data. See the nootropic safety guide.
Key takeaways
| → | The positive landmark trials used bovine PS, which is no longer sold. |
| → | Soy PS evidence is mixed: one 120-person trial found nothing; a 78-person trial found gains only in people with lower starting scores. |
| → | The FDA claim carries the FDA’s own warning that the evidence is very limited. |
| → | Trials used about 300mg a day with meals for 12 weeks to six months; that is a reference, not a minimum. |
| → | Check with your doctor if you take blood thinners, and never buy bovine-derived PS. |
Frequently asked questions
Does phosphatidylserine improve memory?
The bovine PS used in early-1990s trials did, in older adults with memory decline. For the soy PS sold today, one trial found no effect and another found gains only in people with lower starting scores. It is uncertain.
Does the FDA claim mean it’s proven?
No. The claim must carry the FDA’s statement that the research is very limited and preliminary and that there is little scientific evidence supporting it.
Soy or sunflower PS?
Either. Soy has the more direct trial evidence; sunflower suits people avoiding soy. Neither carries the prion concern that led to bovine PS being withdrawn.
How long does it take?
The trials ran 12 weeks to six months, so judge it over months, not days. That is a reference, not a guarantee of any effect.
Can I take it with other nootropics?
Combinations with other nootropics have barely been studied, so the absence of reported problems isn’t proof of safety; add one thing at a time. Pairing it with a choline source is a theory, not a tested combination. See the stacking guide.
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⚕️ Educational Information, Not Medical Advice
This article is educational and is not medical advice. I’m a cognitive enhancement researcher, not a medical doctor. Phosphatidylserine may interact with blood-thinning medicines. Consult a qualified healthcare provider before use, particularly if you take prescription medicines or are pregnant or breastfeeding.
Scientific references
1. Crook, T. H., Tinklenberg, J., Yesavage, J., Petrie, W., Nunzi, M. G., & Massari, D. C. (1991). Effects of phosphatidylserine in age-associated memory impairment. Neurology, 41(5), 644–649. PMID: 2027477 (bovine PS)
2. Cenacchi, T., Bertoldin, T., Farina, C., Fiori, M. G., & Crepaldi, G. (1993). Cognitive decline in the elderly: a double-blind, placebo-controlled multicenter study on efficacy of phosphatidylserine administration. Aging (Milano), 5(2), 123–133. PMID: 8323999 (bovine PS)
3. Jorissen, B. L., Brouns, F., van Boxtel, M. P. J., et al. (2001). The influence of soy-derived phosphatidylserine on cognition in age-associated memory impairment. Nutritional Neuroscience, 4(2), 121–134. PMID: 11842880
4. Kato-Kataoka, A., Sakai, M., Ebina, R., et al. (2010). Soybean-derived phosphatidylserine improves memory function of the elderly Japanese subjects with memory complaints. Journal of Clinical Biochemistry and Nutrition, 47(3), 246–255. J-STAGE
5. Richter, Y., Herzog, Y., Lifshitz, Y., Hayun, R., & Zchut, S. (2013). The effect of soybean-derived phosphatidylserine on cognitive performance in elderly with subjective memory complaints: a pilot study. Clinical Interventions in Aging, 8, 557–563. DOI: 10.2147/CIA.S40348
6. Monteleone, P., Maj, M., Beinat, L., Natale, M., & Kemali, D. (1992). Blunting by chronic phosphatidylserine administration of the stress-induced activation of the hypothalamo-pituitary-adrenal axis in healthy men. European Journal of Clinical Pharmacology, 42(4), 385–388. DOI: 10.1007/BF00280123
7. Glade, M. J., & Smith, K. (2015). Phosphatidylserine and the human brain. Nutrition, 31(6), 781–786. PMID: 25933483
8. U.S. Food and Drug Administration. (2003). Phosphatidylserine and cognitive dysfunction and dementia: qualified health claim, letter of enforcement discretion (Docket No. 02P-0413).
Cognitive Enhancement Researcher | 18+ Years Independent Research
Peter is not a clinician; this guide is educational, not medical advice. It was rewritten in October 2026 to add the null and mixed soy-PS trials, correct the stress-hormone dose, and remove personal effects he could not support. Read about how NeuroEdge Formula evaluates research.
Last reviewed: October 2026 | Educational content only. Not medical advice.
