Nattokinase trial found no clear improvement in overall cognition
An exploratory visuospatial result favored the supplement, but the main global cognition result did not show a statistically significant difference from placebo.
Based on the published abstract. The full paper may contain additional methods, results and limitations.
The 30-second takeaway
Nattokinase did not produce a statistically significant improvement in global cognition compared with placebo in this trial of people with symptom-free arterial narrowing. An exploratory analysis suggested a benefit in visuospatial function, a narrower cognitive domain. That signal should be read alongside the main null result, rather than as evidence of broad cognitive enhancement.
Only 88 participants completed follow-up while taking the assigned treatment as required. The visuospatial finding was exploratory, and the abstract does not establish its clinical importance or whether any benefit persists beyond the study.
What researchers found
Change in Montreal Cognitive Assessment score
Nattokinase versus placebo after 6 months, per-protocol analysis; 95% CI: -1.109 to 1.163; P = 0.948.
What the trial tested
Participants were randomly assigned to supplement or placebo, with cognitive testing and brain imaging before and after treatment. The main reported global cognition comparison concerned score changes on the Montreal Cognitive Assessment.
Reading the mixed results
The global cognition confidence interval included differences in either direction. A separate visuospatial result favored nattokinase, and the authors report consistent intention-to-treat findings. These results leave broad cognitive benefit unproven while identifying a narrower question for further study.
The original publication
Nattokinase supplementation for cognitive enhancement in asymptomatic intracranial/carotid stenosis: A randomized controlled trial.
Zhang K, Zhang X, Wang A et al.
J Stroke Cerebrovasc Dis · 2026
- PubMed ID
- 41325794
- Record checked
AI-assisted research and writing. This explains one selected publication; it is not a complete review of everything known. Our approach.
One more question, understood.
Keep track of the research you’ve explored.