Ashwagandha vs Reishi for Stress: What the Research Shows

Ashwagandha and Reishi are both sold for stress, but their evidence bases point in opposite directions. Ashwagandha has the stronger biomarker record — a 2012 randomized trial found serum cortisol fell 27.9% versus 7.9% on placebo — while a 2025 meta-analysis of the same literature found cortisol dropped without perceived stress improving. Reishi shows the mirror image: no standalone cortisol trial in healthy adults, but the one substantial randomized trial improved fatigue and sense of well-being, the things people actually notice.

Most comparisons of these two treat them as interchangeable adaptogens and assert that both lower cortisol. That framing is wrong in a specific, checkable way. So which should you actually take? Once you separate what's been measured in a biomarker from what's been measured in a questionnaire, the choice gets much clearer — and it stops being a matter of which one is "stronger."

The Short Answer: Which One for Which Kind of Stress?

Ashwagandha suits people whose stress shows up as a dysregulated stress-hormone pattern — wired-and-tired, poor recovery, elevated morning cortisol — because that's the endpoint its trials measured directly. Reishi suits people whose stress shows up as depletion: fatigue, low sense of well-being, difficulty settling in the evening.

That split isn't marketing convenience. It's what the two research literatures actually contain, and neither has been tested head-to-head against the other in a randomized trial. Anyone claiming a clear winner is going beyond the evidence.

What Does Ashwagandha's Stress Evidence Actually Show?

A 2012 randomized, double-blind, placebo-controlled trial in 64 chronically stressed adults found serum cortisol dropped 27.9% after 60 days of 300 mg standardized root extract taken twice daily, against a 7.9% reduction on placebo (Chandrasekhar et al., 2012). That's a large, clean biomarker effect, and it's been broadly reproduced.

The complication arrived in 2025. A systematic review and meta-analysis pooling seven trials on cortisol and six on perceived stress across 488 adults found ashwagandha significantly reduced measured cortisol but produced no significant reduction in self-reported perceived stress versus placebo (Albalawi, Nutrition and Health, 2025).

Ashwagandha's strongest claim is biochemical, not experiential: pooled data from 488 adults show it lowers measured cortisol while leaving perceived-stress scores statistically unchanged. A supplement can move a hormone without changing how a person reports feeling, and in ashwagandha's case the published data show exactly that gap.

So does a hormone that moves without a mood that follows count as a win? It depends entirely on what you're after. If you're tracking labs or managing a measurable cortisol problem, the biomarker is the point. If you simply want to feel calmer, the honest reading is that the questionnaire data don't yet support that promise. Our own coverage of what the ashwagandha research actually shows goes deeper on the withanolide standardisation that determines whether a given product resembles the trial material at all.

What Does Reishi's Stress Evidence Actually Show?

The best trial is a 2005 randomized, double-blind, placebo-controlled study of 132 patients with neurasthenia — a clinical picture dominated by fatigue, irritability, and poor concentration. Over 8 weeks at 1,800 mg of polysaccharide extract three times daily, sense of fatigue fell 28.3% versus 20.1% on placebo, sense of well-being rose 38.7% versus 29.7%, and clinical global impression severity dropped 15.5% versus 4.9% (Tang et al., J Med Food, 2005).

The clinical improvement rate is the number worth holding onto: 51.6% of Reishi patients were rated improved against 24.6% on placebo. Roughly double, on subjective endpoints, in the population most similar to what people now call burnout.

A smaller 2012 pilot supports the same pattern from a different direction. In 48 breast cancer patients with cancer-related fatigue on endocrine therapy, 1,000 mg of Reishi spore powder three times daily for 4 weeks significantly improved physical well-being and fatigue scores, with patients reporting less anxiety and depression (Zhao et al., 2012). It's a pilot, in a specific clinical population, and shouldn't be over-read.

Notice what's absent from both: cortisol. Neither trial measured it as a primary endpoint. Reishi's human evidence is built on how people rated their fatigue and well-being, not on what their stress hormones did.

Why the "Reishi Lowers Cortisol" Claim Doesn't Hold Up on Its Own

This claim is nearly universal in Reishi marketing, and it's the weakest link in most comparisons. There is no published randomized controlled trial of Reishi alone showing reduced cortisol in healthy adults. The claim is generally traced to two things, and neither supports it cleanly.

The first is animal research on Reishi polysaccharides and HPA-axis signalling — mechanistically interesting, but rodent data don't establish a human dose-response. The second is a 2026 randomized controlled trial in 50 adults over 12 weeks that did find reduced cortisol (−5.5%) and ACTH (−8.1%) alongside an 8.7% drop in anxiety scores. The problem: the product tested was a five-mushroom blend containing Lion's Mane, Cordyceps militaris, Reishi, Shiitake, and Maitake. The study design cannot isolate what Reishi contributed.

The frequently cited claim that Reishi lowers cortisol rests on rodent studies and on one 12-week trial of a five-species mushroom blend in 50 adults, where Reishi's individual contribution was not isolated. No randomized controlled trial has tested Reishi alone against placebo on cortisol in healthy adults. Reishi's human evidence for stress is real but sits in subjective endpoints, not hormone measurements.

Worth being precise here: absence of a cortisol trial isn't evidence that Reishi fails to affect cortisol. It just means the claim is currently unsupported for the single ingredient, and a buyer told otherwise is being sold a certainty that doesn't exist. Our article on Reishi and stress resilience covers the triterpene and beta-glucan mechanisms in more depth.

How They Differ in Feel, Timing, and Onset

Reishi is the more noticeably sedating of the two, which is why it's conventionally taken in the evening and why its research clusters around sleep and fatigue rather than daytime performance. Ashwagandha is closer to neutral in most people and works morning or night, though many users prefer evening dosing for its mild calming effect.

Both need weeks, not days. The ashwagandha cortisol trial ran 60 days; the Reishi neurasthenia trial ran 8 weeks; the Reishi fatigue pilot ran 4. Not one of these measured anything at day three. If you're evaluating either after a week, you're evaluating noise. For dose specifics, see our ashwagandha dosage guide and Reishi dosage guide.

There's also a practical difference in what "a dose" means. Ashwagandha trials use 300–600 mg of a standardized extract; the Reishi neurasthenia trial used 5,400 mg of polysaccharide extract daily, split three ways. Reishi doses in research are an order of magnitude larger. So how many retail Reishi capsules would it take to match the trial? For most products on the market, more than anyone is actually taking.

The Safety Profiles Are Not Equivalent

This is where the choice can be made for you, and it deserves more weight than most comparisons give it. The two carry genuinely different risks, not different intensities of the same risk.

Ashwagandha has a documented hepatic signal. A 2020 case series in Liver International described five patients — three from Iceland, two from the US Drug-Induced Liver Injury Network — who developed cholestatic or mixed liver injury with jaundice after 2–12 weeks of use (Björnsson et al., 2020). All recovered without transplant. Separately, a 2018 trial found 600 mg daily measurably raised T3 and T4 and lowered TSH in subclinical hypothyroid patients (Sharma et al., 2018) — helpful for that group, a real problem in hyperthyroidism or Graves' disease. Ashwagandha is also classified as an abortifacient in traditional Ayurvedic texts and isn't recommended in pregnancy.

Reishi's main issue is bleeding. Its triterpenoids, polysaccharides, and lectins inhibit platelet aggregation and can prolong INR, PT, and APTT, so it isn't recommended alongside anticoagulant or antiplatelet medication, in thrombocytopenia, or in the run-up to surgery (Memorial Sloan Kettering Cancer Center). Both carry an immune-stimulation caution for autoimmune conditions.

Put plainly: someone on warfarin should not reach for Reishi, and someone with hyperthyroidism or a history of liver enzyme elevation should be cautious with ashwagandha. That's usually a faster route to a decision than any efficacy argument. Our Reishi side effects and interactions article covers the interaction list in full.

Can You Take Ashwagandha and Reishi Together?

Yes, and it's a common pairing precisely because they aren't redundant. No adverse interaction between the two is documented, and they act on different measured endpoints — ashwagandha on the cortisol axis, Reishi on subjective fatigue and sleep quality. Stacking them targets both halves of the problem rather than doubling down on one.

The practical caveat is attribution. Start one, give it 8 weeks, then add the second. Begin both at once and you'll have no way to tell which is doing the work, or which one is behind a side effect if something goes wrong. Our guide to stacking mushroom supplements safely covers the sequencing in more detail.

How to Choose Between Them

Neither has been tested against the other, so this is a matching exercise rather than a ranking. Working from what each literature actually measured:

• Pick Ashwagandha if you want documented cortisol change, you're tracking biomarkers, your stress presents as poor recovery and wired-and-tired, and you have no thyroid or liver concerns.
• Pick Reishi if your priority is subjective calm, fatigue relief, and evening wind-down, especially where the picture looks like depletion — and you're not on blood thinners or heading for surgery.
• Pick Reishi over Ashwagandha if you're pregnant, hyperthyroid, or have any history of drug-induced liver injury.
• Pick Ashwagandha over Reishi if you take anticoagulants or antiplatelet medication, or have a bleeding disorder.
• Consider both if you have neither contraindication and want to address the hormonal and the experiential side at once — introduced one at a time.

If sleep is the main complaint rather than stress generally, Reishi's sleep and GABA-signalling research is the more relevant starting point. If anxiety is the dominant symptom, our comparison of the best mushroom supplements for anxiety covers a wider set of options.

Frequently Asked Questions

Which is better for stress, Ashwagandha or Reishi?

Neither is better outright, and no trial has compared them directly. Ashwagandha has stronger cortisol evidence — a 27.9% reduction versus 7.9% on placebo in 2012 — while Reishi's 2005 neurasthenia trial improved fatigue and well-being scores, endpoints ashwagandha's meta-analysis failed to move.

Does Reishi lower cortisol like Ashwagandha does?

Not on current evidence. No randomized trial has tested Reishi alone against placebo on cortisol in healthy adults. The 2026 trial reporting a 5.5% cortisol drop used a five-mushroom blend, so Reishi's individual contribution can't be separated out.

Can I take Ashwagandha and Reishi at the same time?

Yes. No adverse interaction is documented, and the pairing is common because they act on different endpoints. Introduce one at a time with about 8 weeks between additions, so you can attribute both benefits and side effects to the right supplement.

Which one is safer?

They carry different risks, not different amounts of the same risk. Ashwagandha has a documented liver-injury case series and raises thyroid hormones. Reishi inhibits platelet aggregation and can prolong clotting times, making it unsuitable alongside anticoagulants or before surgery.

How long before either one works for stress?

Plan on 8 weeks minimum. The ashwagandha cortisol trial ran 60 days and the Reishi neurasthenia trial ran 8 weeks; the shortest positive trial cited here, a Reishi fatigue pilot, still ran 4 weeks. Judging either after a few days tells you nothing.

Shop Ashwagandha and Reishi

Browse our KSM-66 Ashwagandha root extract capsules and our Reishi range — Reishi capsules, dried Reishi fruiting bodies, and Reishi tincture — or see the full selection at amanitamuscariastore.online. Free shipping on orders over €50.

Related Articles

• Ashwagandha Benefits: What the Research Actually Shows
• Reishi and Stress Resilience: What the Research Shows
• Ashwagandha Dosage: How Much to Take Daily
• Reishi Dosage Guide
• How to Stack Mushroom Supplements Safely

Sources

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2. Albalawi AA. Dual impact of Ashwagandha: Significant cortisol reduction but no effects on perceived stress — A systematic review and meta-analysis. Nutrition and Health. 2025. doi:10.1177/02601060251363647
3. Tang W, Gao Y, Chen G, et al. A randomized, double-blind and placebo-controlled study of a Ganoderma lucidum polysaccharide extract in neurasthenia. J Med Food. 2005;8(1):53-58. PubMed 15857210
4. Zhao H, Zhang Q, Zhao L, et al. Spore Powder of Ganoderma lucidum Improves Cancer-Related Fatigue in Breast Cancer Patients Undergoing Endocrine Therapy: A Pilot Clinical Trial. Evid Based Complement Alternat Med. 2012;2012:809614. PMC3236089
5. Björnsson HK, Björnsson ES, Avula B, et al. Ashwagandha-induced liver injury: A case series from Iceland and the US Drug-Induced Liver Injury Network. Liver Int. 2020;40(4):825-829. PubMed 31991029
6. Sharma AK, Basu I, Singh S. Efficacy and Safety of Ashwagandha Root Extract in Subclinical Hypothyroid Patients: A Double-Blind, Randomized Placebo-Controlled Trial. J Altern Complement Med. 2018;24(3):243-248. PubMed 28829155
7. Reishi Mushroom. Memorial Sloan Kettering Cancer Center, Integrative Medicine Herb Database. mskcc.org