Some mushroom species contain compounds that affect nerve cells in lab and animal studies. A small number of human trials, mostly on lion’s mane and cordyceps, have tested memory, reaction time, or cognitive scores with mixed and preliminary results. No mushroom species has enough human evidence to prove it prevents cognitive decline, treats a brain condition, or reliably improves memory in people.
Read This Before You Buy: Interaction and Caution Points
Lion’s mane has one published case report of a hypersensitivity (allergic-type) reaction after oral use. Anyone with a known mushroom allergy should be cautious with any species. Dietary supplements are not tested for drug interactions the way medicines are, so tell your doctor or pharmacist about any mushroom supplement, especially if you take prescription medication, are pregnant or breastfeeding, or have a diagnosed cognitive or neurological condition. The National Center for Complementary and Integrative Health (NCCIH) notes that supplement quality and ingredient amounts can vary between brands and batches, which is a separate risk from the ingredient itself. None of the mushroom species covered here has FDA-approved use for treating, preventing, or curing any brain condition.
The Nerve Growth Factor Hypothesis
Most of the interest in lion’s mane and brain health comes from one idea: certain compounds in the mushroom may encourage nerve cells to produce more nerve growth factor (NGF), a protein involved in the growth and maintenance of nerve cells. Two compound families are usually named in this research. Hericenones come mainly from the fruiting body (the part that looks like a mushroom). Erinacines come mainly from the mycelium (the root-like growing structure). Both have been shown, in cell cultures and in rodent studies, to trigger NGF production or support nerve cell growth.
This mechanism is well documented at the lab and animal level. It has not been confirmed inside a living human brain. No published human trial has isolated hericenones or erinacines alone and tested them directly in people; human studies have used whole mushroom extracts instead, which contain many compounds beyond these two. For a closer look at how these compounds are studied, see our breakdown of hericenones, erinacines, and the NGF research.
Lion’s Mane: What the Human Studies Found
Lion’s mane (Hericium erinaceus) has the most human cognitive research of any mushroom species, though the total body of evidence is still small. A 2025 systematic review identified five randomized controlled trials and three pilot studies in humans testing lion’s mane for cognitive or mood outcomes. The review characterized the human evidence as promising but limited, citing small sample sizes, short trial durations, and inconsistent extract types and doses across studies. Most trials enrolled healthy adults rather than people with a diagnosed memory or cognitive condition, so the findings do not show whether lion’s mane helps people who already have cognitive impairment. Our full lion’s mane research profile covers the safety data and evidence grading in more detail.
Cordyceps: A Smaller but Growing Human Evidence Base
Cordyceps research has focused mainly on exercise and energy, but two recent human trials have looked at cognition directly.
A randomized, double-blind, placebo-controlled crossover trial gave 12 recreationally active men a single dose of Cordyceps militaris before exhaustive cycling. Reaction time on a standard cognitive test (the Stroop task) was faster after cycling in the cordyceps condition than the placebo condition (about 964 milliseconds versus 1,034 milliseconds), with no loss of accuracy. This was a single-dose, small, all-male, exercise-linked study, so it does not show a general memory or brain-health benefit.
A separate 12-week randomized, double-blind, placebo-controlled trial gave 120 adults aged 45 to 65 with self-reported cognitive decline either 300 mg of a standardized Cordyceps militaris mycelial extract or a placebo daily. The treatment group showed improvement on a standard cognitive screening tool and a memory recall test, along with better sleep quality measures, compared to placebo. This is one trial from a single research group; it has not yet been independently replicated, and it used a specific standardized extract that may not match what is in a store-bought product. Our cordyceps evidence and safety page covers the exercise-related research and known cautions.
Reishi: Cognitive Claims Rest on Animal Research
Reishi (Ganoderma lucidum) has a long history of study for cardiovascular and immune outcomes, and a 2025 GRADE systematic review of 17 randomized human trials rated the certainty of evidence for those outcomes as very low. For cognitive and brain effects specifically, the human research is essentially absent. What exists is animal research: studies in rats and mice have found that reishi extracts improved learning and memory tasks and reduced markers of nerve cell damage. A 2023 scientific review of this animal work concluded that “crucial knowledge is still lacking” before those findings can be applied to people. No published human trial has tested reishi for memory or cognitive performance as a primary outcome. See our reishi research profile for the full evidence picture.
Quick Comparison: Human Evidence by Species
- Lion’s mane — 5 randomized trials plus 3 pilot studies in humans (2025 review), mostly in healthy adults. Backed by extensive NGF and nerve-growth research in cells and rodents. Evidence level: limited, promising signal.
- Cordyceps — One small acute exercise trial (12 men) and one 12-week trial (120 adults) that has not been independently replicated. Backed by rodent studies on ischemia-related cognitive impairment. Evidence level: limited and preliminary.
- Reishi — No published human trial has tested cognition as a primary outcome. Backed only by rodent memory and learning studies. Evidence level: animal-stage only.
Human Studies vs. Animal Studies: Why the Difference Matters
A compound that boosts nerve growth factor in a petri dish, or improves a maze-running task in a mouse, has not been shown to do the same thing in a person. Animal and cell studies are useful for finding candidate compounds and generating hypotheses. They cannot show how a compound behaves once it passes through human digestion, crosses into the bloodstream, and reaches the human brain, or whether the dose used in a lab is realistic for a supplement. Only a human clinical trial, ideally randomized, placebo-controlled, and independently repeated, can answer that question. That is why this article separates the two types of evidence for each species instead of combining them into a single claim.
Who Should Use Extra Caution
People with a known mushroom or fungal allergy, people who are pregnant or breastfeeding, people taking prescription medication (especially anything affecting blood clotting, blood sugar, or the immune system), and people with a diagnosed neurological or cognitive condition should talk with a qualified clinician before trying any mushroom supplement. Children were not included in the trials described above, so none of this research applies to pediatric use. The NIH Office of Dietary Supplements recommends telling every healthcare provider about every supplement you take, since interactions and side effects are not always predictable from ingredient lists alone.
Evaluating a Nootropic Mushroom Product’s Claims: A Decision Checklist
- Does the claim name a specific species and study, or does it just say “mushrooms are proven to boost brain power”? Vague claims are a warning sign.
- Was the cited research done in humans, or is it an animal or cell study being described as if it applies to people?
- Does the product match the form tested in research (fruiting body, mycelium, or a specific standardized extract), or is that information missing from the label?
- Is the dose on the label close to what was used in the human trial, or far lower or higher?
- Does the seller promise a specific outcome, like “improves memory” or “prevents cognitive decline,” rather than describing what was actually measured in a study?
- Is there any independent, peer-reviewed replication, or does the claim rest on one small trial?
Evidence Limits
The trials described in this article are small, use different extracts and doses, and mostly involve healthy adults rather than people with diagnosed cognitive impairment. Several key findings, including the 12-week cordyceps trial, come from a single research group and have not been independently repeated. No trial in this research area has run long enough to show whether any of these mushrooms affect long-term risk of dementia or cognitive decline. This article reflects the evidence available as of the current NCCIH and NIH source pages and will be revised if that evidence changes.
Frequently Asked Questions
Can lion’s mane mushroom cure or prevent dementia?
No published human research supports that claim. The available human trials are small, short, and mostly done in healthy adults, not people with dementia or diagnosed cognitive impairment.
Is nerve growth factor (NGF) the same as a brain benefit?
No. NGF is one protein involved in nerve cell health. Compounds that trigger NGF production in a lab do not automatically improve memory or thinking in a person, and this step has not been confirmed in humans for lion’s mane.
Which mushroom has the strongest human evidence for cognition?
Lion’s mane has the most human trials, but the total number is still small (5 RCTs and 3 pilot studies as of the most recent systematic review), and results are described as promising rather than proven.
Should I stop my medication and try a mushroom supplement instead?
No. This article does not recommend starting, stopping, or replacing any medication or treatment. Any change to a medical treatment plan should go through a qualified clinician.
Educational Disclaimer
This article is for general education and summarizes published research. It is not medical advice and does not diagnose, treat, or prevent any condition. Mushroom species, extracts, and doses vary widely, and research findings do not automatically apply to every product sold under the same name. Talk with a qualified healthcare provider before starting any dietary supplement, especially if you are pregnant, breastfeeding, managing a health condition, or taking medication.