Ingredient Guide
Shiitake Explained: The Everyday Mushroom With Immune Research
Shiitake (Lentinula edodes) is a kitchen staple with real human research behind it. What it contains, what the trials found, the raw shiitake caution, and how it fits into Forage.
Explore Mushroom SupportShiitake on the Label
Exactly how much shiitake is in our product, straight from the label.
How to use it (label directions): follow the directions on the Forage label. Each bottle holds 30 servings. How this compares with research doses: the main human trial used 5 to 10 g of dried shiitake a day as food. Forage contains 150 mg of an 8:1 shiitake extract, made from about eight times its weight in mushroom, as one of seven mushrooms, so the amounts are not directly comparable. Use it as directed on the label.
A Kitchen Staple With a Research File
Shiitake (Lentinula edodes) is one of the most widely eaten mushrooms in the world. Native to East Asia, it grows on hardwood logs and has been cultivated in Japan and China for centuries. Its savory, umami flavor makes it a staple in soups, stir-fries and broths.
Shiitake is also one of the few mushrooms with controlled human research in healthy people. Its main active compound is lentinan, a beta-glucan. We include 150 mg of an 8:1 shiitake extract in Forage, alongside maitake, turkey tail, reishi and chaga.
Tip: Cook fresh shiitake thoroughly. Raw or undercooked shiitake is the main cause of a rare skin reaction to lentinan.
How Shiitake Works
Lentinan and Other Beta-Glucans
Lentinan is a beta-glucan from the shiitake cell wall. Beta-glucans are recognized by receptors on immune cells, which is how they are thought to influence immune activity. In a laboratory study with human immune cells, a combination of shiitake, maitake and reishi extracts was a potent activator of macrophages.
Eritadenine
Shiitake contains eritadenine, a compound that affects how the liver handles cholesterol in animal studies. Human evidence for this effect is limited.
Nutrients
Shiitake provides fiber, B vitamins and minerals such as copper and selenium. When exposed to ultraviolet light, it also produces vitamin D.
What Human Studies Found
Immune Markers in Healthy Young Adults
In a 4 week randomized study, 52 healthy adults aged 21 to 41 ate 5 or 10 g of dried shiitake every day. Afterward, two types of immune cells, gamma delta T cells and natural killer T cells, multiplied and activated more readily, salivary IgA (an antibody that lines the gut and airways) rose, and the inflammation marker CRP fell. The researchers concluded that regular shiitake consumption improved immunity under less inflammatory conditions.
A Shiitake Beta-Glucan in Healthy Older Adults
In a 6 week double-blind crossover trial, 42 healthy older adults took 2.5 mg a day of a soluble beta-glucan from shiitake mycelium or a placebo. The beta-glucan increased the number of circulating B cells, a type of antibody-making immune cell, and side effects were similar to placebo.
The honest summary: shiitake has real human evidence for immune markers in healthy people, from eating the whole mushroom and from a purified beta-glucan. Forage uses a smaller extract amount as one of seven mushrooms, so it supports the blend rather than replicating those studies.
Shiitake and Other Forage Mushrooms
Forage combines seven mushrooms. Here is how shiitake compares with two of its neighbors.
| Feature | Shiitake | Maitake | Reishi |
|---|---|---|---|
| Eaten as food | Yes, very common | Yes, prized in cooking | No, too bitter and woody |
| Key compounds | Lentinan, eritadenine | Beta-glucans, D-fraction | Triterpenes, beta-glucans |
| Human trials | Immune markers in healthy adults | Memory in healthy older adults | Several small trials |
| In Forage | 150 mg 8:1 extract | 150 mg 8:1 extract | 200 mg 8:1 extract |
Dosage, Timing, and Stacking
Amounts
The main trial used 5 to 10 g of dried shiitake a day, a food amount. Forage provides 150 mg of an 8:1 extract per serving as part of a blend, so follow the label, and enjoy cooked shiitake as food too.
Timing
Follow the directions on the Forage label.
Stacking
Shiitake already sits with six other mushrooms, Himalayan shilajit and ashwagandha root extract in Forage. For more on how mushroom extracts compare with powders and whole mushrooms, see mushroom extracts vs powders.
Safety and Side Effects
Shiitake is a common food and generally well tolerated. In the beta-glucan trial, side effects were similar to placebo.
Points Worth Knowing
- Raw shiitake reaction: a review of 50 published cases found that a rare, itchy, streaky skin reaction to lentinan followed mostly from eating raw shiitake, and in about a fifth of cases from lightly cooked shiitake. Cook fresh shiitake thoroughly.
- Immune medication: because shiitake influences immune activity, people taking immune-suppressing medication should ask their clinician first.
- Allergy: avoid it if you are allergic to mushrooms.
Who should be cautious: speak with a qualified healthcare professional before using shiitake supplements if you are pregnant or nursing, take immune-suppressing or other regular medication, have had a skin reaction to shiitake, or have a mushroom allergy.
Key Takeaways
- Shiitake (Lentinula edodes) is a widely eaten mushroom rich in the beta-glucan lentinan.
- In healthy young adults, 5 to 10 g of dried shiitake a day for 4 weeks improved immune cell activity and lowered CRP.
- A shiitake beta-glucan raised B cell numbers in healthy older adults, with side effects like placebo.
- Forage contains 150 mg of an 8:1 shiitake extract per serving, with six other mushrooms.
- Cook fresh shiitake thoroughly to avoid a rare skin reaction.
Food First, Then Formula.
Shiitake shows how an everyday food can carry real research. In Forage it adds lentinan to a blend of complementary mushrooms, and in your kitchen it can add even more.
Shiitake FAQ
What are the benefits of shiitake mushrooms?
Shiitake (Lentinula edodes) is a nutritious edible mushroom rich in the beta-glucan lentinan. In a 4 week trial in healthy young adults, eating 5 or 10 g of dried shiitake a day improved immune cell activity, raised salivary IgA and lowered the inflammation marker CRP. It also provides B vitamins, fiber and, when exposed to UV light, vitamin D.
How much shiitake should you eat daily?
The trial that found immune changes used 5 to 10 g of dried shiitake a day, roughly a small handful of fresh mushrooms. Forage provides 150 mg of an 8:1 shiitake extract per serving as part of a blend.
Is shiitake safe for the kidneys?
Shiitake is a common food. People with kidney conditions who follow a special diet, for example one that limits potassium, should ask their care team before using any mushroom supplement.
Is shiitake mushroom psychedelic?
No. Shiitake is one of the world's most widely eaten culinary mushrooms and contains no psychoactive compounds.
Can shiitake cause a rash?
Rarely. Eating raw or undercooked shiitake can cause a streaky, itchy skin reaction to lentinan in sensitive people. Cooking shiitake thoroughly makes this much less likely. Stop and speak with a clinician if you notice a rash.
How much shiitake is in Forage?
Each 2-capsule serving of Forage contains 150 mg of an 8:1 shiitake extract, alongside lion's mane, cordyceps, reishi, chaga, maitake, turkey tail, Himalayan shilajit and ashwagandha root extract.
More on Shiitake
Related guides
Sources
- Dai X, et al. Consuming Lentinula edodes (shiitake) mushrooms daily improves human immunity: a randomized dietary intervention in healthy young adults. Journal of the American College of Nutrition, 2015. PubMed 25866155
- Gaullier JM, et al. Supplementation with a soluble β-glucan exported from Shiitake medicinal mushroom, Lentinus edodes (Berk.) Singer mycelium: a crossover, placebo-controlled study in healthy elderly. International Journal of Medicinal Mushrooms, 2011. PubMed 22164761
- Mallard B, et al. Synergistic immuno-modulatory activity in human macrophages of a medicinal mushroom formulation consisting of Reishi, Shiitake and Maitake. PLoS One, 2019. PubMed 31697749
These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease. Nothing here is medical advice. If you are pregnant, nursing, taking medication (especially immune-suppressing medication), or managing a health condition, consult a qualified healthcare professional before use.