Mushrooms and Ashwagandha: The Ultimate Stress Stack?

Mushroom-Adaptogen Stacks

499 adults

A 2025 randomized, double-blind, placebo-controlled trial tested a reishi and ashwagandha combination for 6 weeks in 499 healthy adults and found significant perceived stress improvement versus placebo. It is the first clinical trial of this combination.

Current Developments in Nutrition, 2025

6 weeks

timeframe at which significant perceived stress reduction appeared in the reishi+ashwagandha RCT

−1.16 µg/dL

cortisol reduction from ashwagandha alone in a 2024 meta-analysis of 488 adults; a measurable biological stress effect

p<0.001

anxiety reduction significance in the 2026 Hisamuddin 5-mushroom blend RCT; mushroom combinations affect stress biomarkers measurably

Current Developments in Nutrition, 2025

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The title has a question mark for a reason. Supplement marketing is full of claims that combinations are "ultimate" or "synergistic" without any evidence those two ingredients have ever been tested together in the same person. For the reishi-and-ashwagandha stack, something unusual happened in 2025: someone actually ran the clinical trial.

This article covers what that trial found, what the individual ingredient evidence looks like, and where the honest answer lands on whether this combination is worth the hype. It's part of the complete mushroom stacking guide, which covers combination strategies across the full range of functional mushrooms.

The First Clinical Trial of Reishi and Ashwagandha Together

Until 2025, every article about taking reishi and ashwagandha together was built entirely on individual ingredient research. Someone who asked "but has anyone tested them in combination?" would have gotten no.

That changed with a randomized, double-blind, placebo-controlled trial published in Current Developments in Nutrition.^[1] The study enrolled 499 healthy adults and tested a supplement containing both reishi mushroom and ashwagandha against a placebo for 6 weeks. Primary outcome: perceived stress, measured with the NIH Toolbox Perceived Stress Scale. Result: the combination group showed statistically significant improvement in perceived stress compared to placebo (p < 0.05).

One disclosure is essential: the study was funded by MegaFood, a supplement company that sells a reishi-ashwagandha product. Industry-funded RCTs produce real evidence; the trial design (double-blind, placebo-controlled, 499 participants) is methodologically sound. But industry-funded trials carry a conflict of interest that should be weighed. The results are more meaningful than zero evidence, and less meaningful than an independent replication.

The trial ran for 6 weeks, which is short relative to some adaptogen research. The effect on perceived stress was statistically significant; the trial does not appear to have reported specific cortisol measurements as a primary outcome. That detail matters because of what a 2024 meta-analysis reveals about ashwagandha's effects on these two outcomes separately.

The Cortisol Story: What Ashwagandha Actually Does to Stress Biology

Ashwagandha (Withania somnifera) has a respectable individual evidence base for stress reduction. A 2019 randomized controlled trial by Lopresti and colleagues tested ashwagandha extract at 240mg per day in 60 adults with self-reported stress for 60 days.^[2] Compared to placebo: significant reductions in morning cortisol and improvements in stress, anxiety, and insomnia. Cortisol reduction is a measurable biological endpoint, and the Lopresti 2019 result is replicated across multiple ashwagandha trials.

The more nuanced picture comes from a 2024 systematic review and meta-analysis of ashwagandha for stress and anxiety, which pooled data from 7 cortisol studies (n = 488 across 6 stress studies).^[3] The cortisol result: statistically significant reduction of 1.16 µg/dL (95% CI: 1.64 to 0.69, p < 0.001). The ashwagandha-vs-placebo difference on cortisol is real and consistent across trials.

The perceived stress result from the same meta-analysis: not statistically significant (SMD = -0.355). Across the aggregate data, ashwagandha's effect on how stressed people said they felt was not reliably different from placebo.

This divergence is scientifically interesting. Ashwagandha measurably lowers cortisol (the biological stress marker). But it doesn't reliably move perceived stress scores (the subjective feeling of being stressed). These two things can come apart, and apparently do for ashwagandha in aggregate data.

Against this backdrop, the 2025 reishi+ashwagandha trial finding (significant improvement in perceived stress) becomes more interesting. Either the combination produces a subjective effect that ashwagandha alone doesn't, or this trial's population, dose, or duration happened to produce a positive perceived stress result that individual ashwagandha trials don't consistently replicate, or the industry funding introduced some result-shifting pressure. The data doesn't resolve this cleanly.

What Reishi Brings to the Stack

Reishi (Ganoderma lucidum) has its own separate clinical evidence for stress-adjacent outcomes, though the landmark trial comes from 2005.

Tang and colleagues ran a randomized, double-blind, placebo-controlled trial of a Ganoderma lucidum polysaccharide extract in patients with neurasthenia, a condition characterized by chronic fatigue, anxiety, and reduced capacity to recover from mental effort.^[4] Compared to placebo: significant improvements in fatigue, anxiety, and quality of life. This trial is the primary human clinical evidence for reishi's adaptogenic effects and remains one of the few placebo-controlled reishi trials to show significant outcomes on stress-related measures.

Reishi's proposed mechanism for stress differs from ashwagandha's. Ashwagandha appears to work primarily via HPA axis modulation, reducing cortisol production and modulating the adrenal glands' stress response. Reishi's polysaccharides interact with the immune system and appear to support sleep quality, which may indirectly reduce the body's stress burden. Reishi's triterpenoids have documented effects on oxidative stress markers.

These mechanisms are at minimum non-redundant. If both ingredients operate through distinct pathways, cortisol suppression on one hand and immune modulation and sleep support on the other, then combining them is at least theoretically additive rather than duplicative. The 2025 trial is the first direct test of this hypothesis, with the caveats about funding noted above.

What Happens When You Add More Mushrooms: The 2026 Multi-Blend RCT

If you want stronger grounds for mushroom combination effects on stress biology, a 2026 randomized controlled trial provides it, though for a mushroom blend rather than a single species plus ashwagandha.

Hisamuddin and colleagues tested a 5-mushroom blend (lion's mane, cordyceps militaris, reishi, shiitake, and maitake) in 50 adults in a double-blind, placebo-controlled design over 12 weeks.^[5] Primary findings: significant reductions in anxiety (State-Trait Anxiety Inventory, p = 0.025 and 0.011; Hamilton Anxiety Rating Scale, p = 0.002), depression (Beck Depression Inventory, p < 0.001 and 0.008), cortisol, ACTH, and fatigue, plus improvements in sleep quality (PSQI). The authors described it as "the first study to evaluate this combination as a potent and safe solution for stress, fatigue and sleep."

The ACTH result is notable. ACTH (adrenocorticotropic hormone) is the signal the pituitary gland sends to tell the adrenal glands to produce cortisol. Showing a reduction in ACTH means the mushroom blend was affecting the stress signaling system at a point upstream of cortisol production, not just cortisol itself. This is the kind of mechanistic detail that separates adaptogenic effects from general relaxation.

The mushroom blend study doesn't include ashwagandha and uses a different combination than the 2025 reishi+ashwagandha trial. But it establishes that multi-mushroom combinations can produce measurable HPA-axis effects in clinical trials, which gives the broader stacking rationale more footing than purely theoretical extrapolation.

Reishi or Lion's Mane: Which Mushroom Pairs Best With Ashwagandha?

This is the practical question, and the honest answer is that only reishi has direct combination evidence. The 2025 trial tested reishi specifically; no published trial has tested lion's mane with ashwagandha.

The theoretical case for lion's mane plus ashwagandha is that the two ingredients target different neurological pathways. Ashwagandha's cortisol reduction operates through the HPA axis and adrenal function. Lion's mane's mood and stress effects have been proposed to involve BDNF (brain-derived neurotrophic factor), a protein that supports neuron health and is depleted by chronic stress. These are distinct mechanisms that may complement each other rather than overlap. The Hisamuddin 2026 5-mushroom blend that showed significant anxiety and cortisol reduction did include lion's mane as one of its five species, though that result cannot be attributed to lion's mane specifically.^[5]

Cortisol reduction plus BDNF support operates through genuinely different biological pathways. If the mechanisms are additive, the combination has theoretical appeal. But "theoretically different mechanisms" is not the same as "demonstrated combination benefit." The absence of a lion's mane plus ashwagandha trial means that the reishi+ashwagandha combination is better-evidenced for stress specifically, while lion's mane may complement it via a different route. For broader coverage on how mushrooms affect anxiety specifically, functional mushrooms for anxiety: what the research shows covers the individual species evidence in depth.

Is This "The Ultimate" Stack? An Honest Answer

The question mark in the title is the honest answer.

The reishi-and-ashwagandha combination now has more direct clinical evidence than almost any other mushroom-plus-adaptogen stack: one industry-funded RCT in 499 adults showing significant perceived stress improvement. That's a lower evidence bar than a well-studied pharmaceutical intervention, but it's more than most supplement combinations can point to. The Hisamuddin 2026 mushroom blend RCT adds context: multi-mushroom combinations do produce measurable HPA-axis changes in controlled conditions.

The caveats are real. Industry funding is a genuine limitation. One trial is not a pattern. The interesting divergence between ashwagandha's cortisol effects (consistent in meta-analysis) and its perceived stress effects (not consistent) means the pathway by which the combination improves subjective stress isn't fully explained by what we know.

"More evidence than anything else in this category" and "ultimate" are not the same thing. The reishi-ashwagandha stack is worth considering if stress management is the goal, with realistic expectations about what a single industry-funded 6-week trial can confirm.

For practical guidance on doses and timing drawn from the research, mushrooms and ashwagandha: stacking adaptogens for stress and fatigue covers the evidence-informed approach. For the broader category of mushroom-adaptogen combinations, including how rhodiola compares to ashwagandha as a pairing partner for reishi, mushroom-adaptogen stacks: what the research supports and reishi and rhodiola for stress and energy cover those comparisons. If you're deciding how long to give any mushroom combination before evaluating it, how long before you feel mushroom supplement effects? covers onset timing from clinical trial data.

The Bottom Line

The reishi-and-ashwagandha combination has more direct clinical evidence than almost any other mushroom-adaptogen stack: a 2025 double-blind RCT in 499 adults found significant perceived stress improvement at 6 weeks, though the trial was industry-funded by MegaFood. Individual ingredient data tells a nuanced story: ashwagandha consistently reduces cortisol in clinical trials but doesn't reliably improve perceived stress in aggregate meta-analysis data, while reishi's 2005 neurasthenia RCT supports fatigue and anxiety benefits. The 2026 Hisamuddin 5-mushroom blend RCT adds mechanistic context: mushroom combinations can measurably reduce cortisol and ACTH in controlled trials.

Frequently Asked Questions

Can you take mushrooms and ashwagandha together?

Yes, and a 2025 double-blind, placebo-controlled trial tested this combination directly in 499 healthy adults. The reishi-and-ashwagandha group showed significant perceived stress improvement versus placebo at 6 weeks. No significant safety concerns were reported in the trial. The study was industry-funded by MegaFood, which is a conflict of interest worth knowing, but the evidence for taking the two together is more established than for most supplement combination claims.

What happens when you combine reishi and ashwagandha?

In the only direct clinical trial of this combination (Current Developments in Nutrition, 2025), 499 adults who took reishi and ashwagandha together for 6 weeks showed significant improvement in perceived stress scores compared to placebo. Separately, ashwagandha is documented to reduce cortisol measurably in clinical trials, while reishi has a 2005 RCT showing fatigue and anxiety improvement in neurasthenia patients. The combination may target stress through both HPA-axis cortisol modulation (ashwagandha's primary pathway) and the immune and sleep-support mechanisms associated with reishi.

Is the mushroom and ashwagandha combination safe?

The 2025 reishi-and-ashwagandha RCT reported no significant adverse events across 499 healthy adult participants at 6 weeks. Both ingredients have individual safety records across multiple clinical trials at standard supplementation doses. There is no published evidence of harmful interactions between reishi and ashwagandha specifically.

Does reishi or lion's mane work better with ashwagandha?

Reishi has direct combination evidence: it was the mushroom used in the only clinical trial of a mushroom-ashwagandha combination (2025, 499 adults). Lion's mane has no published trial testing it with ashwagandha. The theoretical case for lion's mane involves a different mechanism, specifically BDNF and neuroplasticity rather than cortisol, which may complement ashwagandha's HPA-axis effects. But "complementary mechanisms" is not the same as demonstrated combination benefit. On available evidence, reishi-plus-ashwagandha is better supported than lion's mane-plus-ashwagandha.

What is the best mushroom to take with ashwagandha?

Based on the currently available clinical literature, reishi is the best-evidenced pairing: the 2025 Current Developments in Nutrition RCT tested this combination specifically in 499 healthy adults and found significant perceived stress improvement. Lion's mane is a plausible second option based on a different mechanism (BDNF support versus cortisol reduction), but no combination trial with ashwagandha exists for lion's mane. The 2026 Hisamuddin RCT found that a 5-mushroom blend including reishi, lion's mane, cordyceps, shiitake, and maitake reduced cortisol, ACTH, anxiety, and fatigue in controlled conditions.

Sources & References

1. 1RTHM-02468·Gundermann, David et al. (2025). “A conference abstract reporting that a reishi-plus-ashwagandha supplement lowered perceived stress in 499 adults over 6 weeks.” Current Developments in Nutrition.Study breakdown →↩
2. 2RTHM-01102·Lopresti, Adrian L et al. (2019). “An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: A randomized, double-blind, placebo-controlled study..” Medicine.Study breakdown →PubMed →↩
3. 3RTHM-01851·Arumugam, Velan et al. (2024). “Effects of Ashwagandha (Withania Somnifera) on stress and anxiety: A systematic review and meta-analysis..” Explore (New York.Study breakdown →PubMed →↩
4. 4RTHM-00088·Tang, Wenbo et al. (2005). “A randomized, double-blind and placebo-controlled study of a Ganoderma lucidum polysaccharide extract in neurasthenia..” Journal of medicinal food.Study breakdown →PubMed →↩
5. 5RTHM-00959·Hisamuddin, Ahmad Safiyyu'd-Din et al. (2026). “Adaptogenic Effects of Mushroom Blend Supplementation on Stress, Fatigue, and Sleep: A Randomised, Double-Blind, and Placebo-Controlled Trial..” Brain and behavior.Study breakdown →PubMed →↩