Best Phosphatidylserine 2026: Soy vs. Sunflower, Branded vs. Generic
Informational summary — not medical advice. This page ranks product trustworthiness and value at a given dose; on whether PS works, see the hub and the memory page. This statement has not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.
PS's buying problem isn't label fraud — all 6 tracked products disclose actual PS mg. It's source and branding: the trials behind the FDA's claim used bovine-cortex PS, discontinued for decades, so every product sold today is soy or sunflower — a different substance, per EFSA. This page ranks products by disclosed source and branded-vs-generic raw material first, cost per mg second — and flags the one product that labels itself "soy-free" without naming its actual source.
As an Amazon Associate we earn from qualifying purchases. Ranked by disclosed source/branding tier, then cost per mg, never commissions.
The one-line takeaway Don't shop PS on price alone. Check whether the label names a specific source (soy or sunflower) and, ideally, a branded raw material (Sharp-PS®, SerinAid®) — that's the axis the source-shift evidence actually supports weighting. Within a tier, cost per mg is a fair comparison. The single cheapest product overall is a generic, unbranded soy product; the only genuinely soy-free option costs more per mg, and one product's "soy-free" claim doesn't say what the source actually is.
Ranked by source/branding disclosure, then cost per mg
Grouped into four tiers — a lower tier doesn't mean a worse product, only that it discloses less about what's actually in the capsule. All figures include cost at the classic 300mg/day cognition dose, however many capsules that takes. Full data is a public CC BY JSON file.
Branded, genuinely soy-free (sunflower)
| Product | Form | mg/serving | $/serving | $/mg | $/day at 300mg |
|---|---|---|---|---|---|
| Swanson Ultra Sunflower Phosphatidylserine (Sharp-PS Green) | Softgel | 100 mg | $0.43 | $0.0043 | $1.29 |
Branded, traceable soy (Sharp-PS® / SerinAid®)
| Product | Form | mg/serving | $/serving | $/mg | $/day at 300mg |
|---|---|---|---|---|---|
| Doctor's Best Phosphatidylserine (SerinAid) | Veg capsule | 100 mg | $0.25 | $0.0025 | $0.75 |
| Jarrow Formulas PS-100 (Sharp-PS) | Capsule | 100 mg | $0.51 | $0.0051 | $1.53 |
Generic, unbranded soy
| Product | Form | mg/serving | $/serving | $/mg | $/day at 300mg |
|---|---|---|---|---|---|
| Double Wood Phosphatidylserine 300mg | Capsule | 300 mg | $0.35 | $0.0012 | $0.36 |
| NOW Foods Phosphatidyl Serine 100mg | Capsule | 100 mg | $0.31 | $0.0031 | $0.93 |
Soy-free label, source not disclosed (flagged)
| Product | Form | mg/serving | $/serving | $/mg | $/day at 300mg |
|---|---|---|---|---|---|
| Nutricost Phosphatidylserine 400mg (Soy-Free) | Capsule | 400 mg | $0.80 | $0.0020 | $0.60 |
Prices are live Amazon buy-box figures, July 2026; they move. Cost per serving = price ÷ servings per container. Cost per mg = price ÷ (servings × mg per serving). Cost at cognition dose = cost per mg × 300mg, regardless of how many capsules/softgels that requires.
Why source is the real ranking axis for phosphatidylserine
Most supplement categories on this site rank primarily by cost per mg, because once a product discloses its active mg at all, that number is a reasonably reliable comparison point. PS complicates that in a different way than a purity-fraud problem: the mg is honestly disclosed here, but the ingredient itself changed decades ago. The trials behind the FDA's qualified claim (Crook 1991, Crook 1992) used bovine-cortex PS, discontinued industry-wide over BSE risk in the 1990s. Nothing sold today uses it. EFSA's expert panel has formally concluded that bovine- and soy-based PS "are different substances" that "might...have different biological activities" — which means the cost-per-mg number for a soy or sunflower product isn't buying the exact thing the classic positive trials tested.
- Branded raw materials (Sharp-PS®, SerinAid®, Sharp-PS® Green) give you a traceable supply chain and, in Sharp-PS® Green's case, the exact ingredient used in a 2025 published trial (though that trial was null on its primary outcome).
- Generic soy PS is the cheapest per mg but carries no named raw-material traceability.
- A "soy-free" label with no named alternative source is a real, disclosed gap — not proof of anything wrong, just less information than a buyer avoiding soy specifically deserves.
No trial in this evidence base directly compares branded vs. generic PS, or soy vs. sunflower PS, head-to-head on a clinical outcome — this ranking reflects traceability and disclosure, not a proven biological superiority claim for any one source.
Frequently asked questions
What is the best phosphatidylserine supplement?
The cheapest per mg among branded, traceable raw materials (Sharp-PS®/SerinAid®) — not the cheapest number overall, since the classic trials' bovine ingredient is gone and source now matters.
Should I buy soy or sunflower phosphatidylserine?
Soy has more (mostly null) trial history; sunflower has one modern trial (Friling 2025, children, null primary). Choose sunflower only if avoiding soy specifically — it costs more per mg.
What does "soy-free" mean if the source isn't named?
One tracked product labels itself soy-free without disclosing the alternative source — a genuine disclosure gap, not an accusation of wrongdoing.
Is a named raw material worth paying more for?
It buys traceability and matches the ingredient used in published trials — a real reason to pay more, though not proof of superior effect over generic soy PS at the same mg.
Related
- Phosphatidylserine: what it is & who it's for
- PS dosage guide — 300mg cognition dose vs 600-800mg cortisol dose
- PS for age-related memory
- The FDA "qualified" claim, explained
Sources
- Manufacturer labels and live Amazon pricing for all listed products, July 2026. Full dataset: /phosphatidylserine/cost-by-brand.json (CC BY 4.0).
- EFSA Panel on Dietetic Products, Nutrition and Allergies — scientific opinion distinguishing bovine-cortex- and soy-based phosphatidylserine as different substances.
- Friling R, Jackson G, Kennedy D, et al. Sunflower-derived phosphatidylserine (Sharp-PS® Green) in healthy children. Nutr J. 2025. PMID: 41318468 (industry-funded)