What the lion's mane and reishi anxiety trial found

Disclosure first, because this one sits right on top of my business: I formulate and sell functional-mushroom supplements, lion's mane and reishi included. That's a commercial stake in how this trial gets read, and it's the reason I'm going to read it the way I'd want a skeptic to read a trial of my own products. The full disclosure is at the bottom.

The study was published in Frontiers in Nutrition on 20 October 2026 by Ellen F. Smith and Sarah Docherty of Northumbria University in the UK. The same team ran a small 2023 lion's mane pilot in young adults; the single-dose lion's mane study I covered in Report 004 came from a different group. Like that one, this design is better than most of what this category gets.

What they did

Before the trial, the team ran a separate "sort and rank" exercise with 38 young women to find which symptoms mattered most to this group. "Excessive anxiety and worry" came out on top, so anxiety, measured by the GAD-7 questionnaire, became the primary outcome. That primary outcome matches the trial's ClinicalTrials.gov registration (NCT06406946), which is the first thing I check.

Then 84 women aged 18 to 26 (mean age about 22) who said they felt stressed or anxious, but had no psychiatric diagnosis, were randomized to one of three arms for 28 days:

Lion's mane: 1.8 g a day of powdered lion's mane, three 600 mg capsules.
Blend: 1.8 g a day of a powder that was 60% lion's mane and 40% reishi, standardized to 20% beta-glucans.
Placebo: microcrystalline cellulose in matching capsules.

It was double-blind, and the blinding held: when asked to guess, participants couldn't tell which arm they were in (p = 0.34), or even whether they were on an active product at all. Compliance by capsule count was 96.7%. The products were donated by Sempera Organics, which the paper says had no role in design, analysis or the decision to publish; the study itself was paid for with internal university funding, and the authors declare no conflicts.

The headline result, and what it was compared against

On the primary outcome, there was a significant effect of treatment. The blend group scored lower on the GAD-7 than the lion's mane group across the study (6.49 vs 7.76, p = 0.018), and at day 28 the gap widened (4.16 vs 6.50, p = 0.003).

Read that comparison carefully. Both significant primary-outcome comparisons the paper reports are blend versus lion's mane alone. The paper doesn't report a significant difference between the blend and placebo on the GAD-7. So the cleanest thing this trial shows is that one mushroom product did better than another mushroom product. That's useful information. It is not the same as "the blend eases anxiety compared with taking nothing."

There's a second wrinkle the authors raise themselves. Because the blend was 60% lion's mane, the blend arm got about 1.08 g of lion's mane a day while the lion's mane arm got 1.8 g. The two active arms differed in reishi and in lion's mane dose, and there was no reishi-only arm. The authors call the idea that reishi drove the effect "speculative" and say dose-matched single-ingredient arms are the priority for the next trial.

Everyone got better

This is the part I'd put in the headline. Across all three groups, GAD-7 anxiety fell from an average of 10.08 at the start to 5.42 at day 28. That's close to half on average, and the paper reports the drop irrespective of treatment group, whatever was in the capsule. Stress, fatigue and self-esteem all improved significantly over time too, in every arm.

The authors are direct about it. They write that these improvements suggest "trial participation itself may have contributed to psychological benefits, independent of active treatment," and they name expectancy, the Hawthorne effect (people report feeling better when they know they're being watched) and the simple act of tracking your mood every week. They also point out that young women are heavily exposed to social-media marketing of mushroom products, which can shape what participants expect to feel.

Why that matters: if you took a lion's mane blend for a month and felt calmer, this trial says a big share of that is something placebo capsules also deliver. The trial's real question is what's left over after that shared improvement. The answer, so far, is a modest edge for the blend over lion's mane alone.

The secondary results are leads, not findings

The trial also measured anxiety with a second scale (HADS), plus perceived stress (PSS), a stress rating scale, fatigue and self-esteem. Two of those, HADS and PSS, showed treatment effects at the usual p < 0.05 level. After correcting for testing several outcomes at once, both dropped to trend level (q = 0.072). The follow-up comparisons, like the blend beating placebo on stress at day 28 (p = 0.017) or on HADS anxiety two weeks after people stopped taking it (p = 0.001), are labeled exploratory, and the authors say they "should be interpreted cautiously rather than confirmatory." Fatigue, self-esteem and the stress rating scale showed no treatment effect at all.

And lion's mane on its own? It didn't beat placebo on any outcome the paper reports. In the open-ended feedback, the lion's mane group was the most likely to say they'd noticed "no change." That's consistent with the mixed record the authors describe for lion's mane and mood in younger, healthy people.

The size problem

The team aimed for about 135 participants and, because of recruitment problems, randomized 84, roughly 28 per arm. The authors acknowledge wide confidence intervals and say "the precise magnitude of these effects remains uncertain," and that replication "in adequately powered trials is necessary before firm conclusions can be made." They report a post hoc power estimate of 99% and, to their credit, immediately warn that post hoc power calculations have well-documented limitations. I'd weigh the warning, not the 99%.

The groups also weren't identical at the start. They differed on fruit and vegetable intake, waist-to-hip ratio and the stress rating scale, and the analysis adjusted for all three. The placebo group also started with somewhat lower GAD-7 anxiety (9.18 vs 10.59 and 10.38), a difference that wasn't statistically significant. With three arms of under 30 people, small imbalances like these are exactly why one trial isn't the last word.

What the trial doesn't tell you

Which part of the mushroom. The methods describe both products as an organic mushroom "complex" and don't say whether it's fruiting body, mycelium grown on grain, or a mix. That matters for this category (I walked through why in Report 129), and it's the first question I'd ask before assuming any product on a shelf matches what was tested.

How it might work. There were no blood markers. The authors call the lack of mechanistic data "a significant gap" for this study and for the whole functional-mushroom field. Ideas like reishi acting through anti-inflammatory pathways are hypotheses from animal and cell work.

Whether it matters clinically. These were women with self-reported, below-diagnosis stress and anxiety. The authors write that whether the differences "translate into meaningful, or clinically significant benefits" hasn't been established. Nothing here speaks to diagnosed anxiety disorders.

Safety beyond a month. Over 28 days, 50 adverse events were reported by 31 participants, with no differences between groups; the one person who dropped out for an adverse event (a headache) was on placebo. That's reassuring for a month in healthy young adults and says nothing about longer use.

How I'd read it

This is a well-run, pre-registered, properly blinded trial that found a lion's mane and reishi blend did better than lion's mane alone on a pre-specified anxiety score over four weeks, in one small, specific group. It did not show the blend beating placebo on that score, it did not isolate reishi, and the largest effect in the data belonged to simply being in the study. That's a reasonable lead for a bigger trial with dose-matched arms, which is exactly what the authors ask for.

If you see this study used to sell a product, three questions sort the honest pitch from the stretch. Compared with what: placebo, or another mushroom? Which result: the primary outcome, or an exploratory one? And is the product actually the same material, at the same dose, that was tested?

Not medical advice. This is educational analysis, not a recommendation — a study is not a prescription. Talk to a qualified clinician before acting on anything you read here. Full disclaimer →

Disclosure, plainly: I founded and run Shroombiosis (a company I run), which formulates and sells functional-mushroom supplements, lion's mane and reishi among them. That is a direct commercial stake in the exact category this report grades, and the products tested here belong to a competitor. I have no relationship with Sempera Organics, Northumbria University or the authors. Nothing here is sponsored and no link earns a commission; here's the full policy. A recommendation with no stake at all: for performance nutrition, Die Tryin Co. is a fellow combat-veteran-owned brand I'm glad to point people to. I don't own it and earn nothing from the link.