The first randomized test of a reishi-plus-ashwagandha combination reported a significant perceived-stress benefit in 499 adults, but it exists only as a sponsor-funded conference abstract with no published methods, doses, or effect sizes.
Readers comparing combination adaptogen products, and anyone who has seen this trial cited as proof that mushroom-plus-ashwagandha stacks work.
499Healthy adults randomized, the largest sample yet for a mushroom-plus-ashwagandha combination, though reported only as a conference abstract.
What the researchers found
A supplement combining reishi (Ganoderma lucidum) fruiting-body extract with ashwagandha (Withania somnifera) extract improved perceived stress significantly more than placebo over 6 weeks in 499 healthy adults (P < 0.05).
This is the only randomized human comparison of a mushroom-plus-ashwagandha combination against placebo that has been reported to date.
The abstract reports no effect size, no confidence interval, no component doses, and no biological stress markers, so the magnitude and mechanism of the effect cannot be assessed.
The work was funded by MegaFood, which sells the reishi-and-ashwagandha product, and the author group includes company-affiliated and contract-research personnel.
Why it matters
Reishi-and-ashwagandha combination products are sold widely on the premise that stacking adaptogens produces additive stress relief. Until this abstract appeared, that premise rested entirely on extrapolation from separate single-ingredient trials. This is the first direct randomized test of the combination, which makes it important, but its abstract-only status means it cannot yet carry the weight that marketing places on it.
The numbers in context
499 healthy adults randomized; 6-week intervention; perceived stress improved significantly versus placebo at P < 0.05. No effect size, confidence interval, or component dose reported in the abstract.
How the study worked
Virtual (decentralized) randomized, double-blind, placebo-controlled parallel-group trial. 499 healthy adults received either a combination supplement containing Ganoderma lucidum fruiting-body extract and Withania somnifera extract, or a matched placebo, for 6 weeks. Perceived stress was the reported endpoint. Full methodological detail, including randomization procedure, blinding verification, dosing, and analysis population, is not available because the work has been published only as a meeting abstract.
Who was studied
499 healthy adults enrolled remotely; demographic detail not reported in the abstract.
What this study cannot tell us
The dominant limitation is publication format: this is a NUTRITION 2025 meeting abstract, not a peer-reviewed full paper, and it carries no PMID. Consequently there is no reported effect size, confidence interval, component dose, analysis population, or adverse-event table, and the methods cannot be independently appraised. The study was funded by the company that sells the tested product, and the author list includes sponsor-affiliated and contract-research-organization personnel, which raises the usual concerns about selective outcome reporting. Perceived stress is a subjective self-report endpoint, and it was measured without any accompanying biological stress marker, so the abstract cannot distinguish a genuine physiological effect from expectancy. A 6-week duration is short. Finally, because a combination product was tested against placebo rather than against its individual components, the design cannot show that combining reishi with ashwagandha is better than either ingredient alone.
How to read the evidence
Graded low despite a strong design and large sample because the work exists only as a sponsor-funded meeting abstract. Sample size and randomization support the finding; the absence of peer review, effect sizes, doses, and safety data prevents it from supporting confident conclusions.
When this study was published
Presented in 2025. Recent, but still awaiting full peer-reviewed publication.
The bigger picture
Pooled analyses of ashwagandha disagree about whether it reliably shifts perceived stress: Albalawi's 2025 meta-analysis found a significant cortisol reduction but no significant effect on Perceived Stress Scale scores, whereas Arumugam's 2024 meta-analysis did find a significant PSS improvement. This abstract's single endpoint sits precisely in that contested zone, which is another reason to wait for the full publication before treating the combination as established.
Replication
Not yet replicated. No independent randomized trial of a reishi-plus-ashwagandha combination has been reported.
Funding
MegaFood (a Pharmavite brand), which manufactures and sells the reishi-and-ashwagandha supplement that was tested.
Conflicts of interest
The author group includes personnel affiliated with the sponsor and with a contract research organization. As a meeting abstract, no formal competing-interests statement is published.
Questions still open
- How large was the perceived-stress difference, and was it clinically meaningful rather than merely statistically significant?
- What doses of reishi extract and ashwagandha extract did the product actually deliver?
- Would the combination outperform ashwagandha alone in a three-arm design?
- Did any biological stress marker such as cortisol move in parallel with the self-reported change?
- Will the full peer-reviewed publication report the same result?
Common questions
Is this a real clinical trial?
How much reishi and ashwagandha were used?
Does this prove stacking reishi with ashwagandha beats ashwagandha alone?
Read the original research
A Randomized, Double-Blind, Placebo-Controlled Study to Investigate the Effects of a Reishi Mushroom and Ashwagandha Supplement on Perceived Stress in Healthy Adults
Current Developments in Nutrition, 9(Suppl 2), 106183
Abstract supplement of the American Society for Nutrition's NUTRITION 2025 annual meeting, published in Current Developments in Nutrition. Meeting abstracts in this supplement are screened by the conference programme committee, not subjected to full peer review, and carry no PMID.
Citation
Gundermann, David; Ghatak, Somsuvra; Wilcox, Meredith L.; Maki, Kevin C.; Pauli, Emily K.. (2025). A Randomized, Double-Blind, Placebo-Controlled Study to Investigate the Effects of a Reishi Mushroom and Ashwagandha Supplement on Perceived Stress in Healthy Adults. Current Developments in Nutrition, 9(Suppl 2), 106183. https://doi.org/10.1016/j.cdnut.2025.106183