A placebo-controlled pilot trial in which reishi did not significantly beat placebo on mood or quality of life in women with fibromyalgia | Research

The takeaway

Reishi at 6 g/day for 6 weeks did not significantly outperform placebo on mood or quality of life in women with fibromyalgia.

Readers evaluating reishi's role in stress and mood stacks, and anyone told that reishi has human mood evidence behind it.

No significant difference
Reishi did not separate from placebo on any reported mood or quality-of-life outcome in this pilot trial.

What the researchers found

Six grams per day of micro-milled Ganoderma lucidum carpophores for 6 weeks produced no statistically significant between-group differences versus placebo on happiness, depression, satisfaction with life, or health-related quality of life.

A trend toward improved happiness and satisfaction with life and reduced depression was visible within the reishi group when comparing end of treatment to baseline, but within-group trends are not evidence of a treatment effect.

The authors describe the work as a pilot and state that protocol limitations mean further studies are needed.

This is the most directly relevant standalone human trial of reishi against a mood endpoint, and its primary comparison was null.

Why it matters

Reishi is a standard ingredient in adaptogen and stress-relief stacks, and its inclusion is usually justified by mechanism rather than by human outcome data. This trial is one of the few places where reishi alone was tested against placebo on mood endpoints in people, and it did not separate from placebo. That is important context for combination products that rely on reishi to carry a stress claim.

The numbers in context

6 g/day micro-milled Ganoderma lucidum carpophores for 6 weeks. No statistically significant between-group differences on happiness, depression, satisfaction with life, or health-related quality of life.

How the study worked

Double-blind, randomized, placebo-controlled pilot trial in women with fibromyalgia syndrome. One group received 6 g/day of micro-milled Ganoderma lucidum carpophores for 6 weeks; the comparison group received placebo over the same period. Outcomes were happiness, depression, satisfaction with life, and health-related quality of life.

Who was studied

Women with fibromyalgia syndrome.

What this study cannot tell us

This is an explicitly labelled pilot trial, and the authors themselves cite protocol limitations. The sample is small and the study is underpowered, so a null between-group result cannot be read as demonstrating that reishi has no mood effect; it shows only that no effect was detected. The population is women with fibromyalgia, a specific clinical pain population, so the findings do not transfer cleanly to healthy adults using reishi for everyday stress. The 6-week duration is short, and the 6 g/day whole-carpophore dose is not comparable to the concentrated extracts used in most commercial products.

How to read the evidence

Graded as weak null evidence. The randomized, double-blind, placebo-controlled design is appropriate and the blinding protects against expectancy effects, but the pilot sample size leaves the study underpowered, so the null finding is informative about the absence of a large effect rather than conclusive about the absence of any effect.

When this study was published

Published 2020. Still the most directly relevant standalone reishi mood trial.

The bigger picture

Reishi appears in nearly every multi-mushroom stress formulation, including the reishi-plus-ashwagandha combination tested by Gundermann in 2025 and the five-mushroom blend tested by Hisamuddin in 2026. In both of those trials reishi was one ingredient among several and its individual contribution was never isolated. This pilot is one of the only attempts to test reishi alone against a mood endpoint in humans, which makes its null result disproportionately informative about how thin the standalone evidence actually is.

Replication

No direct replication. Reishi's other human mood-adjacent data comes from cancer-related fatigue trials in different populations.

Funding

Not reported in the abstract.

Conflicts of interest

Not reported in the abstract.

Questions still open

Would an adequately powered trial detect the within-group trends as a real between-group effect?
Does a concentrated reishi extract perform differently from 6 g/day of whole milled carpophores?
Would healthy adults under everyday stress respond differently from a fibromyalgia population?
Is reishi contributing anything measurable in the multi-ingredient stress blends that include it?

Common questions

Does this prove reishi does not help mood?

No. It is a small pilot trial, and an underpowered study that fails to find a difference has not shown that no difference exists. What it does show is that reishi did not produce an effect large enough to be detected under proper double-blind placebo-controlled conditions at 6 g/day over 6 weeks.

Why does the summary mention improvements if the result was null?

The reishi group improved relative to its own baseline. That is a within-group change, and it routinely occurs in placebo groups as well through natural fluctuation and expectancy. Only the between-group comparison isolates the treatment, and that comparison was not significant.

Is this dose comparable to a reishi supplement capsule?

Not directly. This trial used 6 g/day of whole milled fruiting body, whereas most commercial products use concentrated extracts at far lower gram amounts, which makes cross-comparison unreliable in either direction.

Read the original research

Ganoderma lucidum Effects on Mood and Health-Related Quality of Life in Women with Fibromyalgia.

Healthcare (Basel, Switzerland), 8(4), 520

Peer-reviewed open-access MDPI journal covering health services and clinical research.

View on PubMed ↗Publisher’s paper ↗

Citation

Pazzi, Francesco; Adsuar, Jose Carmelo; Dominguez-Munoz, Francisco Javier; Garcia-Gordillo, Miguel Angel; Gusi, Narcis; Collado-Mateo, Daniel. (2020). Ganoderma lucidum Effects on Mood and Health-Related Quality of Life in Women with Fibromyalgia.. Healthcare (Basel, Switzerland), 8(4), 520. https://doi.org/10.3390/healthcare8040520