Can Reishi Mushrooms Help With Breast Cancer?

Key Takeaways

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  There’s not enough research to know if reishi supplements improve long-term survival in people with cancer.  

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  A few small studies show certain reishi preparations may enhance immunity and reduce side effects from cancer treatment.

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  Reishi supplements are low-risk for most people, but you shouldn’t take them if you are on immunosuppressants or blood thinners.

In some parts of the world, it’s common for people with cancer and other diseases to take medicinal mushrooms. Rather than eating medicinal mushrooms as food, people usually take them as supplements. One of the most popular medicinal mushrooms is reishi. 

People in parts of Asia have been using reishi for centuries, but more people in other parts of the world are now taking reishi supplements for their health benefits. You can take reishi as a powder, liquid extract, or capsule. Some people also drink reishi mushroom tea. These preparations can contain different substances and have different effects.

Reishi can’t cure cancer, but some studies suggest certain preparations may help the immune system or quality of life.

Only a few small studies have tested the effects of reishi on people with cancer. (In studies, reishi mushrooms are often referred to by their scientific name, Ganoderma lucidum.) Many of these studies have been small. When studies are too small, there's a high risk that their results are due to chance — not due to the effects of reishi.

Immune response

A few small studies in people suggest that some reishi preparations may boost the immune system. One found that a reishi polysaccharide extract, made of complex sugars from the mushroom, may boost the immune response of people with late-stage cancer, for example, by changing blood concentrations of inflammatory molecules and increasing the number and activity of some immune cells. A study found similar results in older women taking reishi extract. Another study found that reishi spore powder boosted the immune systems of people with breast and lung cancer after surgery. 

Cancer treatment response

Studies have found that reishi may enhance how people respond to chemotherapy and radiation. A meta-analysis found that people treated with reishi in addition to chemo or radiation were 1.27 times more likely to respond to treatment than those who didn’t take reishi. But it didn’t look at which parts of the reishi mushroom were used or how they were prepared.

Cancer treatment side effects

Several studies have found that reishi may improve quality of life in people with cancer, but it’s unclear which preparations may have an effect. One study found that a reishi polysaccharide extract may ease symptoms like fever, cough, weakness, sweating, and insomnia. Another study in people with breast cancer getting hormone therapy found that reishi spore powder may improve fatigue and mental health.

Cell and animal studies

Studies in cells and animals are an important early step in research. But you can’t draw conclusions about how things will work in people based on these studies. For example, adding reishi supplements to cells in a lab dish can’t tell researchers how the supplement will be absorbed or broken down in your body. And cancer can behave differently in a mouse than it behaves in a person. These studies are valuable, though, because they help researchers find promising leads and decide if they should test these leads in people.

Some cell and animal studies of reishi suggest that different preparations may help reduce tumor size and growth, fight infections, lower blood sugar, and help the liver to heal after injury. Research also suggests that chemicals in reishi may help protect the body from oxidative damage, which increases the risk of cancer, heart disease, kidney disease, and neurological diseases. These effects need to be confirmed in people.

Taking reishi is generally safe, but always check with your doctor before starting a new supplement. Side effects from reishi are uncommon and may include nausea, insomnia, dizziness, dry mouth, itching, and rash. There is no standard dosing for reishi supplements, so talk to your doctor about how much you should take. 

Reishi may not be safe for people who take immunosuppressants, have an autoimmune condition, or who are receiving immunotherapy. This is because reishi boosts the immune system, which works against immunosuppressants. And it can kick the immune system into overdrive in people with autoimmune disorders or who are receiving immunotherapy. Reishi may also not be safe for people on blood thinners. Stop taking reishi supplements two weeks before surgery because it may increase the risk of bleeding.

Overall, more studies of people are needed to understand if specific reishi preparations can help people with cancer, including breast cancer. Before taking reishi supplements, be sure to talk to your doctor or other health care professionals familiar with reishi, its various preparations, and how it may interact with any conditions you have and medications you take.