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Limited evidenceBrain & cognition

Plasmalogens

A class of brain phospholipids depleted in Alzheimer's disease and sold as scallop- or chicken-derived supplements. One randomized trial found benefit only in subgroups, and independent replication is missing.

Evidence last reviewed: August 2026

What the science says

  • Subgroup benefit in one randomized trial Limited evidence

    A multicenter, double-blind, placebo-controlled trial in patients with mild Alzheimer's disease and mild cognitive impairment found no overall cognitive advantage, with improvement limited to pre-specified subgroups such as younger MCI participants. Blood plasmalogen levels did rise on treatment.

  • Open-label data in cognitive impairment Limited evidence

    An uncontrolled supplementation study in cognitively impaired adults reported increased blood plasmalogens alongside some cognitive and mobility measures. Without a placebo group these results cannot be separated from practice effects and expectation.

Dosage & safety

Studied doseThe randomized trial used 1 mg per day of purified plasmalogens for 24 weeks. Commercial products vary widely in content and purity.
SafetyNo serious adverse effects reported in the small trials to date, but safety data are thin. Marine-derived plasmalogens are a concern for people with shellfish allergy. No data in pregnancy or in children.

Scientific references

Where to buy

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