Cognitive research has moved beyond cells and animals, but the human evidence remains preliminary and cannot support prevention or treatment claims.
| Evidence type | What it shows | Confidence |
|---|---|---|
| Human RCTs | Limited controlled human evidence; topic-specific findings require replication. | |
| Observational human | Associations may exist; causality is unresolved. | |
| Animal | Signals may support human research. | |
| Laboratory | Mechanistic findings do not establish a clinical benefit. |
Observational signals
In a memory-clinic cohort of 470 older adults, lower plasma ergothioneine was associated with poorer baseline cognition and faster decline across several measures over follow-up. A larger community cohort has also reported associations between higher serum levels and lower dementia incidence.
These designs cannot determine whether ergothioneine is causal. Blood levels may reflect diet, health status, metabolism or other factors.
The randomized pilot
A double-blind placebo-controlled pilot enrolled 19 adults aged 60 or older with mild cognitive impairment. Participants assigned ergothioneine took 25 mg three times weekly for one year.
The study reported exploratory differences in learning and a neurodegeneration-related biomarker. With only 19 participants, it is hypothesis-generating—not a basis for clinical recommendations.
How to read the next trial
Look for adequate sample size, prespecified primary outcomes, correction for multiple comparisons, retention, clinically meaningful effect size, independent replication and transparent funding.
Primary references
Reference list last checked Aug. 22, 2026.
Educational information only. This page does not provide personalized medical advice.
Read the full disclaimer →