Yamabushitake mushroom and mild cognitive impairment in a trial
What it found
In a 16-week trial in older Japanese adults with mild cognitive impairment, those taking Yamabushitake mushroom scored higher on a cognitive function scale than those taking a placebo.
Scores fell again in the 4 weeks after they stopped taking it.
What they found
Studies in people
Cognitive scores improved
At weeks 8, 12 and 16, the Yamabushitake group had significantly higher scores on the cognitive function scale than the placebo group.
Scores rose over time
The Yamabushitake group's scores increased the longer they took it.
Scores fell after stopping
At week 4 after the 16 weeks of intake ended, the Yamabushitake group's scores dropped significantly.
No adverse effects in tests, according to the study
Laboratory tests showed no adverse effect of Yamabushitake.
What the authors conclude
“The results obtained in this study suggest that Yamabushitake is effective in improving mild cognitive impairment.”
Also in their conclusions
- They suggest that Yamabushitake is effective in improving mild cognitive impairment.
How it was done
The authors wanted to test whether taking Yamabushitake mushroom by mouth could improve cognitive impairment.
They ran a double-blind, placebo-controlled trial in 50- to 80-year-old Japanese men and women with mild cognitive impairment. After 2 weeks of preliminary examination, 30 subjects were split into two groups of 15; one group took Yamabushitake and the other took a placebo. The Yamabushitake group took four 250 mg tablets containing 96% Yamabushitake dry powder three times a day for 16 weeks, then were observed for 4 more weeks.
What it can’t tell you
- We summarised it from the abstract only.
Who paid
- Authors work at
- Mushroom Laboratory, Japan
The paper
- Title
- Improving effects of the mushroom Yamabushitake (Hericium erinaceus) on mild cognitive impairment: a double-blind placebo-controlled clinical trial
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Abstract only
- Cite
- Mori K, Inatomi S, Ouchi K, Azumi Y, Tuchida T (2009). Improving effects of the mushroom Yamabushitake (Hericium erinaceus) on mild cognitive impairment: a double-blind placebo-controlled clinical trial. Phytotherapy research. doi:10.1002/ptr.2634PubMed 18844328DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error