Is there scientific evidence for the benefits of lion's mane mushroom? An overview of the current state of research

What Is Being Investigated in Lion's Mane Mushroom Research?

Are you using your smartphone to search whether there is truly any scientific basis for Lion's Mane mushroom on nights when you are worried about forgetfulness? This article explains what is being investigated in Lion's Mane mushroom research and how to interpret study results separately from product claims.

What Kinds of Themes Are Being Studied?

Research on Lion's Mane mushroom includes studies investigating cognitive function. One such example is a study published in PubMed (2019). In this trial, participants consumed the fruiting body (the main part of the mushroom) of the Lion's Mane for 12 weeks, and their cognitive function was examined.

This trial was conducted as a randomized, double-blind, placebo-controlled, parallel-group comparison study. Participants were divided into two groups like a lottery draw; one group consumed Lion's Mane, while the other consumed a placebo that looked the same but contained no Lion's Mane. Neither the participants nor the researchers knew which was being consumed during the comparison.

The results indicated that, among several cognitive function tests, significant improvement in cognitive function and suppression of decline were observed only in the Mini-Mental State Examination (MMSE). "Significant" means there was a difference that is unlikely to have occurred by chance.

However, the abstract of the paper does not state how many subjects were involved or whether they were healthy individuals or patients. You cannot judge whether these results apply to you based solely on the abstract.

Lion's Mane research also includes studies targeting healthy adults or people with mild cognitive impairment. Since how you interpret results changes depending on the subjects, make sure to check who the study was targeting when looking at research.

Separating "Efficacy" from Changes Observed in Research

It is recommended to read Lion's Mane research by breaking it down into "who, how much, for how long it was consumed, and what tests were used." For a 12-week study, the only thing that can be written is, "In a study where Lion's Mane fruiting bodies were consumed for 12 weeks, a difference was observed in Mini-Mental State Examination results." You cannot go as far as to say, "Lion's Mane improves cognitive function."

Changes observed in research are results limited to that study's subjects, dosage, duration, and range of testing. On the other hand, the claims that can be displayed on a product are a different matter from the research results. We will organize information regarding labeling in the next chapter based on explanations from the Ministry of Health, Labour and Welfare.

When you see product descriptions claiming it is "good for the brain," try to find out which research they are referring to. Checking the details of the research one by one makes it easier to distinguish between what can and cannot be said. The overall picture of Lion's Mane research is introduced in "What are the Effects of Lion's Mane? The Current Status of Research, How to Eat, and Precautions", so please refer to that as well.

How to View Health Foods to Avoid Confusing Research Results with Product Labeling

Changes observed in research and what can be displayed on a product are not the same. Based on explanations from the Ministry of Health, Labour and Welfare, we will organize the meaning of "health foods" and the scope of what can be labeled. This will make it easier to distinguish between research results and product descriptions when reading them.

Is There a Fixed Definition for "Health Foods"?

The Ministry of Health, Labour and Welfare explains that there is no legal definition for so-called "health foods." The term refers to foods consumed orally that are not pharmaceuticals but are claimed to be useful for maintaining or improving health, or are used for that purpose. Just by the name "health food," it is not clear whether the food has been verified by research.

What Can and Cannot Be Displayed

The Ministry of Health, Labour and Welfare states that general health foods, other than foods with health claims (functional foods), cannot display effects or functions. The fact that changes were seen in research and the ability to write about effects on a product are separate issues. How to view product ingredient labels is introduced in "What Are the Disadvantages of Plant Protein? Explaining How to Read Protein, Carbohydrates, Taste, and Ingredients", so please refer to that as well.

The Strength of Evidence Varies by Type of Research

Even if something is "investigated in research," the scope of what can be claimed changes between experiments using cells and trials targeting humans. We will organize how far you can interpret results for each type of research.

How Far Do Cell and Animal Experiments Go?

If a product description says "in mouse experiments" or "with cultured cells," you should understand that these are not results from testing on humans. Cell and animal experiments, as the name suggests, target non-human subjects. Whether the same results apply to humans can only be known by conducting trials on humans.

How Far Do Human-Targeted Trials Go?

The National Institute of Health and Nutrition explains that for many health food products, effects on humans may not have been investigated. The very existence of human-targeted trials is an important clue for judgment. However, simply having a trial is not enough. Check how many people were involved, for how many days, and what was measured. If the study has few participants and a short duration, the results only apply to the scope of that study's subjects and conditions.

What Is Different About Analyses Summarizing Multiple Studies?

An analysis that collects and summarizes studies on the same theme is called a systematic review. Cochrane indicates that GRADE should be used in systematic reviews to evaluate the certainty of evidence for each outcome. An outcome is an item investigated in a study. If you encounter an article stating that it is "effective," check which item is being evaluated and at what level of certainty.

What Was Found in Studies Targeting Healthy Adults?

In a Lion's Mane study involving 41 healthy adults, the results differed between 60 minutes after a single intake and after 28 days of intake. We will decipher what was observed and what can be said for each.

Results Observed in Healthy Adult Trials (After Single Intake and 28 Days)

A study that randomly divided 41 healthy adults aged 18–45 into a group that consumed Lion's Mane and a group that consumed a comparison substance containing no Lion's Mane (placebo) was reported in a paper published in PubMed (2023). Which was consumed was concealed from both the participants and the researchers (double-blind).

The result was that 60 minutes after a single intake of 1.8g of Lion's Mane, the performance of the Stroop task became faster. There was a significant difference compared to the placebo group, with p=0.005. The Stroop task is a task where, for example, if the word "red" is written in blue, you must answer the color rather than reading the text.

On the other hand, the reduction in subjective stress (stress felt by the individual) after 28 days of intake remained a tendency rather than a significant difference, with p=0.051. Both the items investigated—task performance after single intake and subjective stress after 28 days—were different.

What Can and Cannot Be Said from These Results

What can be said is that, under the conditions of this trial, a difference from the placebo group was observed in task performance 60 minutes after a single intake.

However, you cannot say from the 28-day results that "if you continue, stress will decrease." This is because it was not a result with a clear difference, but remained at the level of a tendency.

Furthermore, you cannot say that daily forgetfulness will decrease. This is because what is reported in this trial is performance on the Stroop task. Since the subjects were healthy individuals aged 18–45, this cannot be directly applied to people aged 46 or older.

This trial is a pilot study with a very small scale of 41 people. A pilot study is a preliminary study conducted before a full-scale, large trial. Whether the same results can be obtained repeatedly must be verified in another trial.

If you see words like "concentration" or "stress" in Lion's Mane product descriptions, distinguish whether it is talking about task performance after a single intake or the tendency after 28 days. It is recommended to accept these results only within the scope of "a difference in task performance was seen after a single intake."

Current Status of Research Targeting People Concerned About Cognitive Function

In Lion's Mane trials targeting people with mild cognitive impairment, reports are very few, and the same results have not been replicated. We will also look at whether it is appropriate to link these results to the prevention or treatment of dementia.

Results Seen in a Very Small Number of Trials Targeting People with Mild Cognitive Impairment

If you are searching because you are worried about a family member's forgetfulness and find a study claiming, "Cognitive function improved with Lion's Mane," first check what kind of people participated.

According to a paper published in PubMed (2024), in a double-blind, placebo-controlled trial targeting patients with mild cognitive impairment, the result was that the cognitive function of those who consumed Lion's Mane improved temporarily. Double-blind is a method where neither the participants nor the researchers know whether Lion's Mane or a placebo is being consumed.

However, the subjects are a very small number of patients. Moreover, these findings have not been replicated. It has not reached the point where the same results have been verified in another study.

This is a different study from the healthy adult trial mentioned earlier, both in participants and in the content of the results. Do not apply results seen in people with mild cognitive impairment to healthy people, or vice versa. It is recommended to read the findings while noting that the improvement was temporary, the number of participants was very small, and it has not been replicated.

Is It Okay to Link This to the Prevention or Treatment of Dementia?

Linking it is not recommended.

The reason is that the results of the aforementioned trial show only temporary cognitive improvement in a very small number of patients. Moreover, the same results have not been replicated. Based on the information presented here, it cannot be said that Lion's Mane is useful for the prevention or treatment of dementia.

Many people interpret the phrase "cognitive function improved" as "dementia got better." However, what was reported in this trial is a temporary change in cognitive function. This is a separate issue from preventing or curing dementia.

People who are concerned about forgetfulness or have already received a diagnosis should not try to handle it with food, but first consult a doctor. For those undergoing treatment, it is important to follow the instructions of your attending physician.

Can Research Intake Methods Be Reproduced with Meals or Commercial Products?

We will compare the amounts, durations, and forms used in Lion's Mane research with what is consumed in meals and commercial products. Even with the same Lion's Mane, conditions can differ. You will also understand how to reconcile products on hand with research and how to differentiate from research on other mushrooms.

How Do the Amounts, Durations, and Forms Used in Research Differ?

The healthy adult trial mentioned earlier had different results between single intake and continuous intake over a certain period. This means that even with the same Lion's Mane, the observed results differed depending on the number of intakes and the duration.

It is recommended to read research introductions on product pages by distinguishing whether it was a single intake or continuous intake, and how much the amount was. Then, compare it with the product's recommended daily intake.

The Difference Between Raw Mushrooms and Powder/Supplements

When standing in front of raw Lion's Mane at the supermarket and powder or supplements at the drugstore, you might be confused about which is closer to the research. The first difference is how the amount is written. Raw mushrooms are in pack weight, powders are by content and recommended single serving, and supplements are by amount per capsule and recommended daily number of capsules; the units of labeling are not unified.

The single-intake trial mentioned earlier indicated the amount in grams. However, there is no data in the materials used for this article showing how many grams of raw mushrooms correspond to that amount. The same applies to powders and supplements. Therefore, it cannot be said that "raw is closer to the research" or "supplements are closer."

How to Reconcile Product Labels with Research Conditions and Differentiate from Other Mushrooms

As mentioned above, for some health foods, the efficacy of the product itself has not been investigated in humans. If you have a Lion's Mane product on hand, read the package label alongside the research conditions. First, check if it is written how many grams of Lion's Mane are contained per recommended daily intake. Some products do not indicate the content from the label, in which case it cannot be compared with the research amount.

Next, compare whether the intake method is a one-time thing or something to continue every day with the way it was consumed in the research. Whether "fruiting body" is written in the ingredient name is also a clue to compare the form. Additionally, the subjects of the aforementioned trial were healthy adults, and their ages were limited. It is good to consider whether you are close to those subjects.

Furthermore, avoid reading research results for other mushrooms, such as Maitake, as evidence for Lion's Mane. Other mushrooms have their own separate research. If research is introduced in a product description, it is recommended to confirm which mushroom the research actually investigated.

When You Have Pre-existing Conditions or Are Taking Medication, Who Should You Consult Before Trying?

We will provide guidance on what is known about the safety of Lion's Mane itself, and who people with pre-existing conditions or those taking medication should consult before trying it.

What Is Not Known About Safety Data for Lion's Mane Itself

The materials covered in this article do not contain data investigating the safety of Lion's Mane itself. Therefore, the safety of Lion's Mane cannot be judged from these materials. What is not known should be accepted as not known.

People with Pre-existing Conditions or Taking Medication Should Consult a Doctor or Pharmacist

The Ministry of Health, Labour and Welfare's "Correct Usage of Health Foods" states that cases have been reported where the combined use of health foods and pharmaceuticals has affected the action of the pharmaceuticals or the person's physical condition. People with pre-existing conditions or who are taking medication should consult a doctor or pharmacist before trying them. For those undergoing treatment, it is important to follow the instructions of your attending physician.

Product	Content	Carbohydrates	Artificial Sweeteners	White Sugar	Protein (Source)
Calorie Mate Chocolate Flavor	80g (4 bars)	39.7g	None	Used	8.7g / Soy, Wheat
1-Pon Manzoku Bar Protein Strong Cocoa	70g	15g	Used (Aspartame, Acesulfame K)	Used	30g / Soy, Milk
SAVAS Protein Bar Chocolate Flavor	44g	Not listed (Sugar 7.6g)	Used (Sucralose)	Used	17.2g / Milk, Soy
in Bar Protein Baked Bitter	42g	2.3–5.0g	Used (Sucralose)	Used	15.9g / Milk, Soy
BRAIN PRO	35g	4.9g	None	None	11.1g / Plant-based (Pea)

The numerical values for each product are based on the nutritional information posted on each manufacturer's official website as of September 25, 2026. Values may change due to product revisions.

Frequently Asked Questions

Have the effects of Lion's Mane been scientifically verified?

It cannot be said that they have been sufficiently established. While trials targeting humans have been reported, there are trials with very few participants, trials with limited items investigated, and trials where the same results have not been replicated. The changes observed are limited to the scope of the subjects and conditions of each trial. The contents of each trial are organized in the chapters "Studies Targeting Healthy Adults" and "Research Targeting People Concerned About Cognitive Function."

If effects are seen in research, can the same effects be expected from commercial products?

It cannot be said that the same effects will be obtained. Research is conducted with fixed amounts, durations, and forms. Whether the recommended daily intake or form of commercial products is the same must be verified on the package label. Products that do not indicate content from the label cannot be compared with research amounts. There is also no data confirming how much raw mushrooms or powder corresponds to trial amounts in this article. Please see the chapter "Can Research Intake Methods Be Reproduced with Meals or Commercial Products?" for how to compare them.

Summary

There is research on Lion's Mane targeting humans. However, due to conditions such as small scale, limited items investigated, and results not being replicated, it is not at a stage where it can be asserted that there is sufficient basis for efficacy. When you see research in product descriptions, it is recommended to check who was targeted, how much was consumed, for how long, and in what form. Please consult your family doctor regarding any concerns.