What is the reishi mushroom, also known as Ganoderma lucidum and lingzhi, is a fungus that grows in various hot and humid locations in Asia (1Trusted Source).

For many years, this fungus has been a staple in Eastern medicine (1Trusted Source2Trusted Source).

Within the mushroom, there are several molecules, including triterpenoids, polysaccharides, and peptidoglycans, that may be responsible for its health effects (3Trusted Source).

While the mushrooms themselves can be eaten fresh, it is also common to use powdered forms of the mushroom or extracts that contain these specific molecules.

These different forms have been tested in cell, animal, and human studies.

Below are 6 scientifically studied benefits of the reishi mushroom. The first three are backed by stronger evidence, while support for the others is less conclusive.

What is The Reishi Mushroom?

1. Boost the Immune System

One of the most important effects of the reishi mushroom is that it can boost your immune system (4Trusted Source).

While some details are still uncertain, test-tube studies have shown that reishi can affect the genes in white blood cells, which are critical parts of your immune system.

What’s more, these studies have found that some forms of reishi may alter inflammation pathways in white blood cells (5Trusted Source).

Research in cancer patients has shown that some of the molecules found in mushrooms can increase the activity of a type of white blood cell called natural killer cells (6Trusted Source).

Natural killer cells fight infections and cancer in the body (7Trusted Source).

Another study found that reishi can increase the number of other white blood cells (lymphocytes) in those with colorectal cancer (2Trusted Source).

Although most immune system benefits of reishi mushroom have been seen in those who are ill, some evidence has shown that it can help healthy people, too.

In one study, the fungus improved lymphocyte function, which helps fight infections and cancer, in athletes exposed to stressful conditions (8Trusted Source, 9Trusted Source).

However, other research in healthy adults showed no improvement in immune function or inflammation after 4 weeks of taking reishi extract (10Trusted Source).

Overall, it is clear that reishi impacts white blood cells and immune function. More research is needed to determine the extent of the benefits for the healthy and ill.

SUMMARYReishi mushroom can enhance immune function through its effects on white blood cells, which help fight infection and cancer. This may occur primarily in those who are ill, as mixed results have been seen in those who are healthy.

2. Anti-Cancer Properties

Many people consume this fungus due to its potential cancer-fighting properties (1112Trusted Source).

In fact, one study of over 4,000 breast cancer survivors found that around 59% consumed reishi mushrooms (13Trusted Source).

Additionally, several test-tube studies have shown that it can lead to the death of cancer cells (14Trusted Source15Trusted Source16Trusted Source).

Yet the results of these studies do not necessarily equate to effectiveness in animals or humans.

Some research has investigated if reishi could be beneficial for prostate cancer due to its effects on the hormone testosterone (1718Trusted Source).

While one case study showed that molecules found in this mushroom may reverse prostate cancer in humans, a larger follow-up study did not support these findings (19Trusted Source20Trusted Source).

Reishi mushroom has also been studied for its role in preventing or fighting colorectal cancer (2Trusted Source21Trusted Source).

Some research showed that one year of treatment with reishi decreased the number and size of tumors in the large intestine (21Trusted Source).

What’s more, a detailed report of multiple studies indicated that the mushroom can beneficially affect cancer patients (22Trusted Source).

These benefits included increasing the activity of the body’s white blood cells, which help fight cancer, and improving the quality of life in cancer patients.

However, researchers state that reishi should be administered in combination with traditional treatment rather than replacing it (22Trusted Source).

What’s more, many of the studies on reishi mushrooms and cancer were not high-quality. Because of this, much more research is needed (1123Trusted Source).

SUMMARYAlthough reishi mushroom appears to hold some promise for cancer prevention or treatment, more information is needed before it becomes part of standard therapy. However, it may be appropriate to use in addition to normal care in some cases.

3. Could Fight Fatigue and Depression

Reishi’s effects on the immune system are often most emphasized, but it has other potential advantages as well.

These include reduced fatigue and depression, as well as improved quality of life.

One study examined its effects in 132 people with neurasthenia, a poorly defined condition associated with aches, pains, dizziness, headaches, and irritability (24Trusted Source).

The researchers found that fatigue was reduced and well-being was improved after 8 weeks of taking the supplements.

Another study found that fatigue was reduced and quality of life was improved after 4 weeks of taking reishi powder in a group of 48 breast cancer survivors (25Trusted Source).

What’s more, the people in the study also experienced less anxiety and depression.

While reishi mushroom may hold promise for people with certain diseases or illnesses, it is not clear if it would benefit those who are otherwise healthy.

SUMMARYSome preliminary studies have shown that reishi mushroom could decrease anxiety and depression as well as improve quality of life in those with certain medical conditions.

4–6. Other Potential Benefits

In addition to its effects on the immune system and quality of life, reishi mushroom has been studied for its potential to improve other aspects of health.

4. Heart Health

One 12-week study of 26 people showed that reishi mushrooms may increase “good” HDL cholesterol and decrease triglycerides (26Trusted Source).

However, other research in healthy adults showed no improvement in these heart disease risk factors (10Trusted Source).

Moreover, a large analysis demonstrated no beneficial effects on heart health after examining five different studies containing around 400 people. The researchers found that consuming reishi mushrooms for up to 16 weeks did not improve cholesterol (27Trusted Source).

Overall, more research is needed in regard to reishi mushrooms and heart health.

5. Blood Sugar Control

Several studies have indicated that molecules found in the reishi mushroom can decrease blood sugar in animals (28Trusted Source29Trusted Source).

Some preliminary research in humans reported similar findings (30).

However, the majority of research has not supported this benefit. After evaluating hundreds of participants, researchers found no benefits for fasting blood sugar (27Trusted Source).

Mixed results were seen for blood sugar after meals. In some cases, reishi mushroom lowered blood sugar, but in other cases, it was worse than a placebo.

Again, more research is needed here as well.

6. Antioxidant Status

Antioxidants are molecules that can help prevent damage to your cells (31).

Because of this important function, there is substantial interest in foods and supplements that can enhance antioxidant status in the body.

Many claim that reishi mushroom is effective for this purpose.

However, several studies have found no change in the levels of two important antioxidant enzymes in the blood after consuming the fungus for 4 to 12 weeks (10Trusted Source26Trusted Source).

SUMMARYA small amount of research has shown that reishi mushroom could improve good cholesterol or blood sugar. However, the majority of the research indicates that it does not improve cholesterol, blood sugar or antioxidants in the body.

Dosage Recommendations Vary Based on the Form Used

Unlike some foods or supplements, the dose of reishi mushroom can vary substantially based on which type is used (12Trusted Source).

The highest doses are seen when someone consumes the mushroom itself. In these cases, doses may range from 25 to 100 grams, depending on the size of the mushroom (3233).

Commonly, a dried extract of the mushroom is used instead. In these cases, the dose is approximately 10 times less than when the mushroom itself is consumed (10Trusted Source).

For example, 50 grams of reishi mushroom itself may be comparable to approximately 5 grams of the mushroom extract. Doses of the mushroom extract vary but typically range from approximately 1.5 to 9 grams per day (27Trusted Source).

Additionally, some supplements use only certain portions of the extract. In these cases, the recommended doses may be much lower than the values reported above.

Because the suggested dose can vary widely based on which form of the mushroom is used, it is very important to know which type you are taking.

SUMMARYThe dose of reishi mushroom varies based on the form of the fungus, so it is important to know which form you are using. Consuming the mushroom itself provides higher doses, while extracts provide lower doses.

Possible Side Effects and Dangers

Despite its popularity, there are those who have questioned the safety of reishi mushrooms.

Some research found that those who took reishi mushroom for 4 months were almost two times as likely to experience a side effect as those taking a placebo (22Trusted Source).

However, these effects were minor and included a slightly increased risk of upset stomach or digestive distress. No adverse effects on liver health were reported.

Other research also indicated that four weeks of taking reishi mushroom extract did not produce any detrimental effects on the liver or kidneys in healthy adults (10Trusted Source).

In contrast to these reports, significant liver problems have been reported in two case studies (34Trusted Source35Trusted Source).

Both of the people in the case studies had previously used reishi mushrooms without problems but experienced adverse effects after switching to a powdered form.

This makes it difficult to know for certain if the mushroom itself was responsible for the observed liver damage or if there were problems with the powdered extract.

It is also important to note that many studies of reishi mushrooms have not reported safety data, so limited information is available overall (22Trusted Source).

Nevertheless, there are several groups of people who should probably avoid reishi.

These include those who are pregnant or breastfeeding, have a blood disorder, will be undergoing surgery or have low blood pressure (36).

SUMMARYSome studies of reishi mushroom have not provided safety information, but others have reported that several months of taking it is likely safe. Nonetheless, several cases of severe liver damage have been associated with reishi extract.

The Bottom Line

Reishi mushroom is a popular fungus used in Eastern medicine.

It may boost the immune system through its effects on white blood cells, particularly in people who are ill, such as those with cancer.

This fungus may also be able to decrease the size and number of tumors in certain types of cancer, as well as improve the quality of life for some cancer patients.

Most human research has shown that it does not improve cholesterol, blood sugar, or antioxidants, but it may be effective at reducing fatigue or depression in some cases.