Shiitake

Other names Shiitake Mushroom, Lentinula Edodes, Sawtooth Oak Mushroom, Black Forest Mushroom, Oakwood Mushroom, Golden Oak Mushroom

Shiitake is a mushroom used by many people as food. When certain active ingredients from it are included in extracts, it may yield several cognitive benefits, including improvements in mood, energy, and memory. But is it actually effective? Read on to find out what the science says.

This nootropic has no healthy human placebo-controlled studies that meet our inclusion criteria. Negative side effects can occur if used carelessly, so make sure you’re aware of the risks of Shiitake.

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Benefits

Read about the effects of Shiitake in relation to the amount of evidence we've found

Why do people use shiitake?

People who self-experiment with shiitake often state they use it to improve their:

Mood
Energy
Focus
Memory
Sociality

There is a lack of scientific evidence for the effectiveness of shiitake for any of these purposes, especially in healthy humans

Can shiitake boost your mood?

No studies have examined the effects of shiitake mushrooms on mood in healthy humans. It is impossible to know if it can enhance mood in the average healthy person.

In one study which examined the effects of shiitake in cancer patients [1], lentinan (β-1,3-Glucan) which is an active ingredient in shiitake, improved quality of life after 12 weeks of daily use. There was no control group in this study.

In another study [2], lentinan improved quality of life in cancer patients when compared with a control group.

Shiitake impacts levels of inflammation and the immune system [3], both inflammation and immune system functioning have an impact on mood [4][5].

Shiitake may improve mood, or it may not, the data in healthy humans that is needed to find has not been collected so far.

Can shiitake improve cognition and brain health?

No studies have examined the effects of shiitake mushrooms alone on cognition in humans.

In one study [6], it was found that the consumption of various mushrooms was associated with, not necessarily the cause of, reduced risk of cognitive decline.

This evidence is not very robust. While it is promising that the effects that were found were positive, it is impossible to do anything with these findings in practice since the study only examined correlation, not causation. Another catch with this study was that the consumption of many different mushrooms (total mushroom servings per week) were studied. Shiitake was only one of many mushrooms, so it is possible that one of the other mushrooms is responsible for all of the cognition-preserving effects that were found. Moreover, the study showed that cognition was preserved better in people who consumed more mushrooms, not that it was enhanced from a solid baseline.

While consuming mushrooms might be good for your long-term brain health, valid conclusions cannot be made with confidence as regards the efficacy of shiitake products for cognitive enhancement.

Risks

The legality and side effects of Shiitake

You should always consider the risks of a nootropic before you use it.

Negative side effects of shiitake

Since active ingredients in shiitake modulate the immune system, consumption can lead to negative side effects in people with particular genetic predispositions

Shiitake dermatitis is a rare side effect of shiitake consumption [7] which occurs in 2% of people who consume raw or lightly cooked mushrooms [8], but it is not impossible to get it even if you cook the mushrooms well [9]. Contact your doctor if marks that are red and look like you have scratched yourself really hard and long appear on your skin during the 72h after the use of shiitake products. The skin problems usually disappear fully within 8 weeks.

When 10 people consumed 4g shiitake powder daily for 10 weeks [10], "provoked blood eosinophilia, increased eosinophil granule proteins in serum and stool, and increased gastrointestinal symptoms", but these problems went away after stopping the use of shiitake powder. This a large dose for a prolonged period. If you experience severe symptoms of a compromised immune system while taking shiitake, contact your doctor.

Side effects

Interactions

Supplements and drugs can interact with Shiitake to increase or decrease the positive or negative effects you experience. If you are already using any supplements or drugs, speak with your trusted medical professional before you experiment with Shiitake. To learn more about the potential interactions between Shiitake and other substances, use interaction-checker.

Legality

Is your country not included? Learn how to find out if Shiitake is legal in your country.

Legality Disclaimer

FAQ

Frequently asked questions about Shiitake

What forms of shiitake products are there?

There is the shiitake mushroom which can be consumed as a food, and then there are shiitake extract powder supplements, such as the one available via our affiliate partner Nootropics Depot.

What micronutrients are in shiitake mushrooms?

Per 100g of dried shiitake mushrooms, the following are the most relevant micronutrient amounts [12]:

Zinc: 7.66mg
Copper: 5.165mg
Vitamin C: 3.5mg
Riboflavin (vitamin B2): 1.27mg
Niacin (vitamin B3): 14.1mg
Pantothenic acid (vitamin B5): 21.879mg
Pyridoxine (vitamin B6): 0.965mg
Choline: 201.7mg

This means that shiitake mushrooms are an especially good source of copper and vitamin B5.

Which active ingredient in shiitake is most relevant to its effects on mood and cognition?

Beta-glucans, specifically lentinan (β-1,3-Glucan), is the most studied compound in humans and one of the active ingredients in shiitake that is likely most involved in its cognitive and affective effects.

Fun fact: shiitake contains acetylcholine, the "memory neurotransmitter" [13]. The relevance of its acetylcholine contents is questionable since there may be very little ACh present in the mushroom.

What other foods contain beta-glucans?

Oats and yeast extract.

Should you use shiitake?

One thing that is certain about the effects of shiitake is that we know relatively little about them. There is a lack of high-quality research, especially in healthy humans.

Because of the lack of research on shiitake, we never recommend that people use it.

If you have already decided to use it, here are some guidelines to maximize the benefits and minimize the risks.

How much and how often should you use shiitake?

There are different forms of shiitake products. If you are planning on eating mushrooms, they should be well-cooked and 15g is generally considered as one serving. One to three servings per day is likely safe.

Different extract powders should be taken in different doses. For example, the one available via our affiliate partner Nootropics Depot should be taken in dosages between 500mg and 1g daily.

What time of day should you take shiitake?

There is no data on what the optimal time of day for the use of shiitake is. There is no evidence that shiitake impair sleep if taken before bed-time, or that it should not be taken in the morning.

Studies

Studies conducted on the effects of Shiitake in healthy humans

Last updated Saturday, June 10, 2023