Benefits
May support verbal memory in healthy middle-aged and older adults
In a 12-week placebo-controlled trial of 66 healthy Japanese adults aged 40 or older, chosen because their verbal memory was below average, 1 mg a day raised the verbal memory score more than placebo and met the primary endpoint by a narrow margin. The company that supplies the material funded the study, and it has not yet been repeated.
Studied for memory in early cognitive decline
In the biggest trial, 328 older adults with mild cognitive impairment or mild Alzheimer's took 1 mg a day or placebo for 24 weeks. The main cognitive score did not differ between groups. A memory scale improved more on plasmalogen only in subgroups of the mild Alzheimer's patients, namely women and those under 77, which is a lead to test rather than a result to rely on.
Attention and mental concentration in small trials
The healthy-adult trial also found better simple and complex attention scores than placebo, but these were secondary results without correction for multiple comparisons. A separate four-week trial in 40 male college athletes taking 2 mg a day reported better performance on a timed concentration test. Both used capsules from the same manufacturer.
Mood and sleep signals from one small trial
In the college athlete trial, the overall mood disturbance score fell more on plasmalogen than on placebo, but that primary result fell just short of statistical significance. Anger and fatigue subscales improved clearly, and an insomnia score dipped slightly at two weeks, again just short of significance versus placebo. One four-week study in 40 young men cannot establish a mood effect.
Blood plasmalogen levels rose only in an uncontrolled pilot
In an uncontrolled pilot of 10 people with Parkinson's disease, 1 mg a day for 24 weeks brought low blood ether phospholipid levels close to those of healthy controls. Placebo-controlled trials did not confirm this: in the largest, blood levels did not differ between groups overall, and in the athlete trial at 2 mg a day they changed similarly in both groups. Whether any reaches the brain is unknown.
Mechanism of action
Vinyl ether phospholipids in brain membranes
Plasmalogens carry a vinyl ether bond at the first position of the glycerol backbone, often with a polyunsaturated fatty acid at the second. Both are prime targets for reactive oxygen species, which is why these brain-enriched lipids are thought to act as membrane antioxidants.
Lower levels in the Alzheimer's brain
A postmortem study of Alzheimer's brains traced the loss of phosphatidylethanolamine in the frontal cortex and hippocampus to a specific drop in its plasmalogen subclass. Supplementation aims to replace that loss, but a deficit does not prove that adding more helps.
Microglial inflammation signaling in cell and mouse studies
In cultured microglia, scallop plasmalogens reduced inflammation-triggered TLR4 receptor internalization and caspase activation, and in Alzheimer's model mice they reduced the same TLR4 change in the brain. Cell and animal work only, from a lab that collaborates with the trial group.
BDNF signaling and a proposed receptor route
In mice, plasmalogens raised hippocampal BDNF alongside better learning, and in neuronal cells this ran through ERK and Akt signaling to CREB. The trial group proposes that plasmalogens act in small amounts at G protein-coupled receptors, which would explain effects at 1 mg. In human trials, plasma BDNF did not differ from placebo.
Brain uptake is the open question
The brain appears to control its own lipid supply. In ether lipid-deficient mice, an oral ether lipid precursor raised blood ether lipids but did not restore brain plasmalogens. That study did not test scallop plasmalogen, but it leaves brain delivery an open question.
Clinical trials
Multicenter, randomized, double-blind, placebo-controlled 24-week trial of 1 mg/day purified scallop plasmalogen given as a jelly (Fujino T, Yamada T, Asada T, Tsuboi Y, Wakana C, Mawatari S, Kono S 2017, EBioMedicine 17:199-205, PMID 28259590).
328 patients aged 60 to 85 with MMSE-J scores of 20 to 27, covering mild Alzheimer's disease and mild cognitive impairment; 276 completed the trial.
In the intention-to-treat analysis there was no significant difference between groups on the primary outcome (MMSE-J) or on the secondary outcomes, and enrollment fell short of the 181 per group the authors calculated they needed. Among mild Alzheimer's patients the Wechsler memory score improved on plasmalogen (between-group P=0.067), with significant between-group differences only in the female (P=0.017) and under-77 (P=0.029) subgroups. Adverse events were similar in both arms. The trial was funded by the Japanese Plasmalogen Society; B&S Corporation, a donor to the society, supplied the test material, and two authors had filed patent applications on a manufacturing method for ether phospholipids.
Randomized, double-blind, placebo-controlled 12-week trial of 1 mg/day (two 0.5 mg capsules) plasmalogen purified from Mizuhopecten yessoensis (Fukuchi M, Tanaka M, Nagata M, Takara T, Sasuga Y 2026, Front Nutr 13:1906996, PMID 42656342).
68 cognitively healthy Japanese adults aged 40 or older with below-average verbal memory at baseline; 66 were analyzed.
The primary outcome, standardized verbal memory on the Cognitrax battery, was higher on plasmalogen than on placebo at 12 weeks (difference 10.1 points, 95% CI 0.4 to 19.9, p=0.042). Simple and complex attention also favored plasmalogen as secondary outcomes that were not adjusted for multiple comparisons, while visual memory, psychomotor speed and reaction time did not differ. Plasma BDNF rose in both groups alike. No adverse events were reported. The study was funded by B&S Corporation, which supplied the test capsules, and two authors were employees or officers of the company.
Randomized, double-blind, placebo-controlled 4-week trial of 2 mg/day scallop-derived plasmalogen (Fujino M, Fukuda J, Isogai H, Ogaki T, Mawatari S, Takaki A, Wakana C, Fujino T 2022, Front Cell Dev Biol 10:894734, PMID 35721497).
40 male university athletes aged 18 to 22 who completed treatment, 20 per group.
The primary outcome, the Total Mood Disturbance score of the POMS 2, fell more on plasmalogen, but the between-group difference was only marginal (p=0.07). The anger-hostility and fatigue-inertia subscales improved significantly versus placebo, and performance on the Uchida-Kraepelin concentration test was better. Physical performance and laboratory values did not differ. The trial was funded by the Japanese Plasmalogen Society, and the capsules were made by B&S Corporation.
Uncontrolled preliminary study of 1 mg/day purified scallop ether phospholipids for 24 weeks (Mawatari S, Ohara S, Taniwaki Y, Tsuboi Y, Maruyama T, Fujino T 2020, Parkinsons Dis 2020:2671070, PMID 32148751).
10 patients with Parkinson's disease, with blood levels compared against 39 age-matched healthy controls.
Baseline plasma and red blood cell ether phospholipid levels were lower than in controls and rose to almost normal levels by 24 weeks, and the authors reported that some clinical symptoms improved at the same time. With ten patients, no placebo group and no blinding, the symptom findings cannot be separated from placebo response or natural fluctuation.