VITAMINS & SUPPLEMENTS · GUIDE
Phosphatidylserine Sources: Soy, Sunflower, Cabbage-Derived and Label Claims
What the FDA letters say about soy-derived and cattle-brain-derived phosphatidylserine, why early trial results may not carry over between sources, and how to read PS labels.
Content last updated . This page has not been medically reviewed.
Back to PhosphatidylserineQuick answer
Phosphatidylserine (PS) in supplements can come from different raw materials. The two the FDA discussed in its 2003 and 2004 letters were cattle brain cortex and soy lecithin, and the FDA said it was uncertain whether they have similar effects. [1] Sunflower-derived and cabbage-derived PS: not described in the sources we read, so we cannot say how they compare. This page is about reading labels; it gives no advice on what to take. The overview is on the phosphatidylserine page.
What the FDA letters say about the source
| Point | What the source says |
|---|---|
| Source used in the studies that showed benefit | The FDA's 2004 update says that of four relevant studies, three showed benefit using bovine (cattle) brain cortex PS, and the one with no benefit used soy-derived PS. [1] |
| Are soy and bovine PS the same? | The FDA cites "considerable uncertainty" about whether they have similar effects, because the fatty-acid makeup may differ. [1] |
| Purity of soy PS | The 2003 letter says soy-derived PS must be "of very high purity" for the claim. [2] |
| Cattle source | The 2003 letter says bovine-derived sources must not come from cattle born, raised or slaughtered where BSE exists. [2] |
| Evidence level | The FDA described the research as very limited and preliminary. [1] |
These are US FDA letters from 2003 and 2004. We did not read newer FDA statements or EU, Canadian or UK documents, so we cannot say how sourcing is handled in those places today.
Soy and allergy
If a product says it contains soy-derived PS, people with a soy allergy should ask a pharmacist or allergist before using it. We did not find a source we could read on whether PS products can trigger soy allergy, so we do not say whether they can. See reading supplement labels. Allergic reactions with swelling or trouble breathing are an emergency: call 911 in the US.Why the source matters for reading research
Trials are tied to the PS that was tested, not to PS in general. The FDA noted the studies with benefit used bovine PS, so a soy-derived product is not automatically covered by them. [1] Newer trials often use mixed products. For example, a 12-month trial used capsules containing PS together with alpha-linolenic acid, ginkgo flavonoids and B vitamins, so its results cannot be assigned to PS alone. [3] A stress-hormone trial used a soy-based PS and phosphatidic acid complex, which is also not plain PS. [4] See the evidence page.Reading a label
- Source named? A label may say soy, sunflower or another origin, or give no origin. The sources we read do not tell us what each term means in practice, so treat an absent origin as an open question to ask a pharmacist.
- Amount per serving and form. Is it PS alone or a complex or blend? Study results apply only to the tested product type.
- Health claims. The FDA's 2003 wording must state that the FDA concludes there is little scientific evidence supporting the claim. [2] Be wary of memory or dementia claims without that kind of qualification. Disease-prevention claims have drawn FDA warnings for related brain products. [5]
- Quality. See quality testing and certifications and how supplements are regulated.
Frequently asked questions
Is soy-derived phosphatidylserine the same as bovine-derived?
The FDA said there is considerable uncertainty about whether they have similar effects. [1]
Which source did the studies with benefit use?
In the FDA's 2004 review of four relevant studies, the three that showed benefit used bovine brain cortex PS; the one that did not used soy-derived PS. [1]
Is cabbage-derived or sunflower-derived PS better?
Not described in the sources we read, so we cannot compare.
Is PS safe for people with a soy allergy?
We did not find a source we could read that answers this; ask an allergist or pharmacist.
Does an FDA claim mean PS works?
No. The 2003 wording must say the FDA concludes there is little scientific evidence for it. [2]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety and who should ask first
Interactions, pregnancy, breastfeeding, children, kidney, liver and surgery information for PS: Proper evidence not found in the sources we read. Ask a clinician or pharmacist, and see medication interactions and supplements before surgery. Never stop or change a prescribed medicine because of a supplement.
References
- US Food and Drug Administration, Letter updating the phosphatidylserine and cognitive function and dementia qualified health claim, November 24, 2004 (listed on FDA's qualified health claims page; read in FDA's archived copy). Read 2026-10-23.
- US Food and Drug Administration, qualified health claim letter, Phosphatidylserine and Cognitive Dysfunction and Dementia, issued May 13, 2003 (listed on FDA's qualified health claims page; the letter was read in FDA's archived copy). Read 2026-10-23.
- Duan H et al. J Affect Disord 2025. Effects of a food supplement containing phosphatidylserine on cognitive function in Chinese older adults with mild cognitive impairment: a randomized double-blind, placebo-controlled trial. Read 2026-10-23.
- A soy-based phosphatidylserine/phosphatidic acid complex (PAS) normalizes the stress reactivity of hypothalamus-pituitary-adrenal-axis in chronically stressed male subjects: a randomized, placebo-controlled study. Lipids Health Dis 2014. PubMed record. Read 2026-10-23.
- US Food and Drug Administration (with the Federal Trade Commission), Warning letter to an online seller of nootropic products, 565425 (February 5, 2019). Read 2026-10-23.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.