Shiitake: what is it, what does it contain, and what should you look out for?
Short answer: Shiitake (Lentinula edodes) is an edible mushroom from East Asia, known from cooking and available as a supplement in powder or capsules. It contains compounds including the beta-glucan lentinan, eritadenine, and ergothioneine, but has barely been studied in humans. The main thing to note: raw or undercooked shiitake can cause a streak-like rash in some people.
Last updated: November 3, 2026 · Written by Florian Fermin
Shiitake is actually the odd one out in our mushroom lineup. Most people know it from stir-fries, not as a supplement.
There’s one thing I’m really strict about with shiitake: cooking it thoroughly. Read on to find out why.
What is shiitake, and where does its name come from?
Shiitake is an edible mushroom from East Asia that naturally grows on dead deciduous wood, especially that of the shii tree, an Asian relative of oak and beech. The name comes from shii (the tree) and take, Japanese for mushroom. Today, shiitake is cultivated all over the world on logs or sawdust.
Shiitake is popular in cooking for its firm texture and umami flavor. As a supplement, shiitake is available as dried powder or in capsules.
Labels sometimes use the older scientific name Lentinus edodes. It is the same species.
What compounds are in shiitake?
In addition to fiber, protein, and B vitamins, shiitake contains four compounds that often come up in research: lentinan, eritadenine, ergothioneine, and ergosterol. For safe use, lentinan is the most important. It is considered the suspected cause of the rash you can get from raw shiitake, and it breaks down when heated.
| Compound | What is it? | Good to know |
|---|---|---|
| Lentinan | A beta-glucan from the cell wall | Broken down by heating; the suspected cause of the rash from raw shiitake |
| Eritadenine | A compound mainly known from shiitake | Studied mainly in animals |
| Ergothioneine | An antioxidant found in mushrooms | Found in various mushrooms, including shiitake |
| Ergosterol | A sterol that partially converts to vitamin D2 under UV light | Vitamin D content depends on exposure to light |
| Fiber, protein, and B vitamins | General nutrients | As in most mushrooms |
Beta-glucans are chains of sugars found in the cell walls of mushrooms and grains. Lentinan is the beta-glucan found specifically in shiitake. Ergothioneine is a sulfur-containing amino acid derivative that people can only get through their diet.
How does shiitake work? What does human research say?
What shiitake does in your body has barely been studied in humans. Research on lentinan, eritadenine, and ergothioneine has mostly been conducted in cell cultures and animals. So the findings are still limited.
No health claims have been approved in the EU for shiitake itself, so we make no promises about what it does in your body. Shiitake is a food and dietary supplement, not a medicine.
Why should you always cook shiitake thoroughly?
Some people develop an itchy, streaky skin rash after eating raw or undercooked shiitake. The rash looks as though the skin has been struck with a whip. Thorough cooking is the solution because the suspected cause, lentinan, breaks down with heat (Stephany et al., 2016).
The rash usually appears within hours to a few days and goes away on its own, but may last for weeks (Stephany et al., 2016). Not everyone reacts this way. It affects some people who eat raw or undercooked shiitake.
- The suspected cause is lentinan, which breaks down when thoroughly cooked.
- The French food safety authority ANSES also warns that shiitake should always be cooked thoroughly, whether fresh, dried or powdered (ANSES, 2021).
- If you develop a skin rash after using shiitake, stop and contact your doctor.
| Preparation | Skin rash | Advice |
|---|---|---|
| Raw (for example, in a salad) | Reported | Avoid |
| Undercooked | Reported | Cook for longer |
| Thoroughly cooked (soup, broth; wok only if cooked long enough and all the way through) | Lentinan breaks down with heat | Recommended preparation |
What other side effects and points should you keep in mind with shiitake?
Aside from this skin rash, little is known about the side effects of shiitake as a supplement, as it has hardly been studied in people. Shiitake is, however, well known as a regular food. Certain groups should consult a doctor or pharmacist before using a shiitake supplement.
Consult your doctor or pharmacist first if you:
- take medication
- are pregnant or breastfeeding
- are allergic to mushrooms
How do you use shiitake safely in the kitchen?
To use shiitake safely in the kitchen, always cook the mushrooms thoroughly, for example in soup, broth, a stir-fry or a stew. According to ANSES, briefly stir-frying them may sometimes not be enough, so cook them in the wok for long enough to make sure they’re thoroughly cooked. Soak dried shiitake in water first, and use the soaking water as broth. It’s best to avoid raw shiitake in salads or on carpaccio.
Fresh shiitake stems are tough. You usually remove them or simmer them in broth.
Slice the caps so they cook evenly. Use shiitake powder as an umami flavor enhancer in soup or sauce that simmers thoroughly. Always let it simmer for a while.
Shiitake powder or capsules: which form should you choose?
Shiitake is available fresh or dried, as powder and in capsules. Use fresh and dried shiitake in dishes, cook powder into hot dishes or broth, and capsules are tasteless and provide a fixed amount. Whichever form you choose, always heat whole shiitake thoroughly before use.
| Form | What is it? | Good to know |
|---|---|---|
| Fresh or dried shiitake | The whole mushroom | Always heat thoroughly before use |
| Shiitake powder | Dried, ground shiitake | Cook into hot dishes, soup or broth |
| Shiitake capsules | Ground shiitake in a capsule | Tasteless, fixed amount |
What is the difference between shiitake powder and capsules?
If you choose shiitake as a supplement, we offer a choice of powder and capsules. Both contain dried, ground shiitake, not an extract. The difference is in taste, convenience and how you take it.
| Shiitake powder | Shiitake capsules | |
|---|---|---|
| Contents | 60 g, with measuring spoon | 60 capsules of 500 mg |
| Ingredients | Organic shiitake only | Organic shiitake and a plant-based capsule (HPMC), with no fillers |
| Directions for use | 1-2 scoops (1-2 g), 1-2 times a day | 2-3 capsules, 1-2 times a day |
| Taste | Savory, umami | None |
| Useful if | you want to cook it into soup, sauce or broth | you don't want to taste your shiitake |
If you often make soup or stew, powder is convenient. If you don't want to think about it, capsules are easier.
What is in shiitake powder?
Shiitake powder is dried, finely ground shiitake. Per 100 g, our powder contains 291 kcal, 21.7 g of protein and 41.3 g of fiber.
Not sure which mushroom powder is right for you? In functional mushrooms: which one is right for you?, we compare the different types.
Always follow the daily dose on the packaging. You can read exactly what our labels say below.
What does the GOYU shiitake packaging say?
We sell shiitake as 60 g of organic powder and as organic capsules (60 capsules of 500 mg), both certified under control code NL-BIO-01 and sourced from non-EU agriculture. The packaging gives specific instructions for each serving. We have a certificate of analysis (CoA) for every batch.
- Shiitake powder (60 g): "Take 1-2 scoops once or twice a day (about 1-2 g). Preferably during or right after a meal." At 1 g per day, one pouch lasts 60 days; at 4 g per day (2 scoops, twice a day), it lasts 15 days.
- Shiitake capsules (60 x 500 mg): "Take 2-3 capsules once or twice a day with water." That's 1,000 to 3,000 mg per day, or 10 to 30 days per jar.
- Nutritional value of the powder: per 100 g, 41.3 g of fiber and 21.7 g of protein.
- Name on the label: the packaging uses the older name Lentinus edodes, the same species as Lentinula edodes.
For our shiitake powder and capsules: Shiitake is naturally high in protein** and Shiitake is naturally high in fibre**
**Approved health claim (Regulation (EU) No 432/2012) or nutrition claim (Regulation (EC) No 1924/2006).
The powder has 10 reviews on getgoyu.com with an average rating of 4.4, and the capsules have 11 reviews with an average rating of 4.45 (Judge.me, October 2026). The package directions do not mention how to prepare it. Use the powder in hot dishes that cook thoroughly, such as soup or broth, and always let it simmer for a while.
What should you look for when buying a shiitake supplement?
When buying a shiitake supplement, look for four things: which part of the mushroom was used, whether the product is certified organic, whether it has been lab-tested for heavy metals and microbiology, and whether it contains shiitake only. This information should be on the label or in a certificate of analysis.
- Fruit body or mycelium: does it state which part was used? I would personally choose the fruit body. Learn more in fruit body or mycelium.
- Certified organic
- Lab testing for heavy metals and microbiology, with a certificate of analysis (CoA)
- Purity: shiitake only, or also fillers and excipients?
Want an overview of all seven criteria? Read how to choose the best mushroom supplement.
How does shiitake compare to other mushrooms?
Shiitake is primarily an edible mushroom, while reishi, chaga and lion's mane are usually used as supplements. Each contains different compounds, so they are not interchangeable. Research on one species cannot simply be applied to another.
Also read our articles on reishi, chaga and lion's mane, or browse all forms in our mushroom collection.
Summary in 3 points
- Shiitake (Lentinula edodes) contains lentinan, eritadenine, ergothioneine and ergosterol, as well as fiber and protein.
- Shiitake has barely been studied in humans. Most research is in labs and animals, and there are no approved health claims.
- Raw or undercooked shiitake can cause a skin rash. Always cook shiitake thoroughly and stop eating it if a rash occurs.
Frequently asked questions
Can you eat shiitake raw?
Preferably not. Raw or undercooked shiitake can cause a skin rash in some people. Always cook shiitake thoroughly.
How long does the rash last?
The rash usually develops within hours to a few days and goes away on its own, but can last for weeks. See your doctor if you develop a rash.
What is lentinan?
Lentinan is a beta-glucan from the shiitake cell wall. It is broken down by heating and is the suspected cause of the skin rash associated with raw shiitake.
Does shiitake contain vitamin D?
Shiitake contains ergosterol, which is partially converted into vitamin D2 under UV light. The amount of vitamin D depends on how the mushroom was exposed to light and dried.
What is shiitake powder?
Shiitake powder is dried, finely ground shiitake. It has a savory taste and can be added to soups, sauces, or broth while cooking. Our powder contains only organic shiitake, with a suggested use of 1-2 scoops (1-2 g) 1-2 times per day.
Is shiitake as a supplement the same as eating shiitake?
It’s the same mushroom, but you use it differently. Powder and capsules are dried, ground shiitake in a fixed amount per day. You eat fresh or dried shiitake in a dish, and always cook it thoroughly. A shiitake extract is another product: certain compounds are concentrated in it. So check the label to see what you’re buying.
Is shiitake the same as other mushroom supplements?
No. Shiitake, reishi, chaga, and lion's mane are different species, each with its own composition.
Sources
- Stephany MP, Chung S, Handler MZ, Handler NS, Handler GA, Schwartz RA. Review article on skin reactions after eating shiitake. Am J Clin Dermatol. 2016;17(5):485-489. Europe PMC 27566177
- ANSES and DGCCRF (2021). Notice on thoroughly cooking shiitake before consumption. April 9, 2021. anses.fr
- Customer reviews of shiitake powder and capsules on getgoyu.com. Judge.me, October 2026.
Find all forms of our shiitake on the buy shiitake page.
This article is for informational purposes only and is not medical advice. Dietary supplements are not a substitute for a varied and balanced diet and a healthy lifestyle. If in doubt, pregnant, or taking medication, consult your doctor or pharmacist.
