Introduction to Reishi Mushrooms
Reishi mushrooms, also called Ganoderma lucidum or Ling Zhi, are known as the “mushroom of immortality.” People in China and other Asian countries have used them for thousands of years to help with health and boost the immune system. They grow on hardwood trees like plum trees and look shiny and reddish brown. Today, people don’t usually eat Reishi mushrooms in meals because they taste bitter and are tough to chew. Instead, they are sold as supplements, powders, or teas. Many people wonder if Reishi can help with serious illnesses like cancer. But is it safe, and does it really help?
What’s Inside Reishi Mushrooms?
Reishi mushrooms are special because they have over 400 active compounds! The two most important are called beta-glucans and ganoderic acids. These are thought to help the immune system fight off germs and maybe even cancer cells. Reishi is low in calories—about 15–20 calories per cup of dried powder—and has 3–5 grams of carbs per 10 grams. It also has fiber, a little protein, some B vitamins, and minerals like potassium and selenium. The fiber comes from polysaccharides, which are also good for immunity.
How Reishi Might Fight Cancer
Scientists have tested Reishi mushrooms in labs to see how they might affect cancer. They found that Reishi could block some pathways that cancer cells use to survive and grow. Some of these pathways include PI3K/AKT/mTOR, NF-κB, and VEGF, which help cancer cells grow, spread, and make new blood vessels. Beta-glucans can help the body’s natural killer (NK) cells and T cells find and destroy cancer cells. This is like training your immune system to be a better guard dog against tumors!
Reishi’s Effect on Antioxidants
One thing to know is that Reishi acts as an antioxidant by supporting something called glutathione. Glutathione helps protect healthy cells from damage. This can be good for normal cells but tricky for cancer treatment because some cancer cells can also use glutathione to hide from treatments that cause oxidative stress. That’s why some people, like me, don’t use Reishi during treatments that rely on oxidative damage to kill cancer cells.
Evidence from Studies
Some studies show that Reishi mushrooms might help certain cancers. For example, in mice with inflammatory breast cancer, tumors shrank by about 60% when treated with Reishi. Some human studies found that people with colon polyps who took Reishi had fewer or smaller polyps later. Other research found that Reishi helped the immune system work better for people with lung cancer and gastric cancer. But, these studies were small, and we still need more research to know if Reishi really works the same in people.
Does Reishi Help with Quality of Life?
Besides fighting cancer cells, Reishi mushrooms might help cancer patients feel better during tough treatments like chemotherapy. Some small trials say that people taking Reishi feel less tired, sleep better, and have less nausea. Patients also reported better appetite and mood. So, while Reishi is not a cure, it may help people feel stronger and more comfortable while they fight cancer. But remember, the U.S. FDA does not approve Reishi as a cancer drug—it’s sold as a supplement only.
Safety and Side Effects
For most people, Reishi mushrooms are safe to take for up to one year. Some people might get side effects like dry mouth, dizziness, rash, or an upset stomach. Rarely, high doses can cause diarrhea or liver problems. People who take blood thinners should be careful because Reishi might make you bleed more easily. Reishi can also lower blood pressure, so talk to your doctor if you take medicine for that. There’s not enough safety info for pregnant or breastfeeding women. Always ask your doctor before adding Reishi to your routine.
Combining Reishi with Other Mushrooms
Some people like to combine Reishi with turkey tail mushroom because they can work together to boost the immune system. But keep in mind, this adds more carbs, which may not fit strict low-carb or fasting cancer diets. That’s why I skip Reishi in my protocol because it brings extra carbs and boosts glutathione, which I try to keep low to help my oxidative stress treatments work better.
Why I Choose Not to Use Reishi
I personally skip Reishi for now. Even though it blocks cancer pathways and boosts NK and T cells, the carbs and antioxidant effects don’t fit my plan. I focus on starving cancer cells of sugar and lowering glutathione so my treatments can do more damage to cancer cells. Reishi’s mild protection could help cancer cells survive those treatments. So for me, other compounds work better for my protocol.
Observational Studies on Mushrooms
Some large studies looked at people who eat more mushrooms, including Reishi, and found they may have a lower risk of total cancer. One meta-analysis found people who ate more mushrooms had about 30% less risk of getting cancer, especially breast cancer. But these studies don’t prove Reishi alone does this. Many other mushrooms like shiitake and maitake are eaten too, so it’s hard to tell which one helps most.
What Research Still Needs to Be Done
Right now, most Reishi research is done in labs or on animals. Human trials are small, and they don’t all use the same dosages or mushroom parts. Some studies use mycelium, others use spores, and some use extracts, so results can be very different. We need bigger, better trials with more people to know if Reishi really works against cancer in humans. Scientists should also check how safe it is to use long term.
How Much Reishi Should You Take?
There’s no official dose for Reishi mushrooms, but most supplements recommend 1.5 to 9 grams daily. That’s about 20 milligrams per kilogram of body weight. It’s smart to choose brands that standardize the amount of beta-glucans and ganoderic acids. Always buy from trusted companies because supplement quality can vary a lot.
What About FDA Approval?
The FDA does not approve Reishi mushrooms as a treatment for cancer or any disease. That means companies can sell it as a dietary supplement, but they can’t say it cures or treats cancer. Because of this, you should always be careful and do your research before taking any mushroom supplements, especially if you are already on cancer treatment.
Can Reishi Be Part of a Cancer Plan?
Reishi mushrooms might help your immune system and make you feel better during chemo, but they shouldn’t replace real medical treatments like surgery, radiation, or chemotherapy. Think of Reishi as something that may help you feel stronger, not as a stand-alone cure. Talk with your doctor or oncologist before adding it to your plan.
Putting It All Together
Reishi mushrooms have been called the “mushroom of immortality” for good reason. They contain powerful compounds that boost your immune system and may block cancer survival pathways. Some people feel better when they take Reishi, but it’s not a magic bullet. It can have side effects and may not fit every cancer plan.
Final Thoughts
If you’re curious about using Reishi mushrooms during cancer treatment, do your homework and talk with your doctor. Reishi might help your immune system and quality of life, but it shouldn’t replace proven cancer treatments. Always check the quality of the supplement and use it safely. Your health plan should fit you, and Reishi is just one small piece of the puzzle.
Research Links and References
Below is a list of key studies and sources referenced in this overview, providing further details on reishi mushrooms and their potential role in cancer treatment:
- National Cancer Institute. Mushrooms – NCI. www.cancer.gov. Published: 2024-07-10.
- WebMD. Reishi Mushrooms: Health Benefits, Safety Information, Dosage, and More. www.webmd.com. Published: 2024-12-27.
- Penn State University. Higher mushroom consumption is associated with a lower risk of cancer. www.psu.edu. Published: 2021-04-20.
- Memorial Sloan Kettering Cancer Center. Reishi Mushroom. www.mskcc.org. Published: 2023-02-08.
- PubMed. Medicinal Mushroom Supplements in Cancer: A Systematic Review of Clinical Studies. pubmed.ncbi.nlm.nih.gov.
- Cancer Research UK. Mushrooms | Complementary and Alternative therapy. www.cancerresearchuk.org. Published: 2022-11-03.
- ScienceDirect. Higher Mushroom Consumption Is Associated with Lower Risk of Cancer: A Systematic Review and Meta-Analysis of Observational Studies. www.sciencedirect.com.
- ScienceDirect. Symptom improvements and adverse effects with Reishi mushroom use: A Cross-Sectional survey of cancer patients. www.sciencedirect.com. Published: 2024-11-30.
- The ASCO Post. Reishi Mushroom. ascopost.com. Published: 2018-08-09.
- PMC. Anti-Tumor Effects of Ganoderma lucidum (Reishi) in Inflammatory Breast Cancer in In Vivo and In Vitro Models. pmc.ncbi.nlm.nih.gov.
- WebMD. Reishi Mushroom: Uses and Risks. www.webmd.com. Published: 2023-05-29.
- Masonic Cancer Center. Minnesota Cancer Clinical Trials Network Funds Reishi Mushroom Study for Breast Cancer Patients in 2022 Grant Program. cancer.umn.edu. Published: 2022-07-11.
- PMC. Ganoderma lucidum (Reishi mushroom) for cancer treatment. pmc.ncbi.nlm.nih.gov. Published: 2016-05-03.
- The Nutrition Source. Mushrooms. nutritionsource.hsph.harvard.edu. Published: 2020-03-19.
- PMC. Ganoderma lucidum (Reishi mushroom) for cancer treatment. pmc.ncbi.nlm.nih.gov.
- ScienceDaily. Higher mushroom consumption is associated with a lower risk of cancer. www.sciencedaily.com. Published: 2021-04-20.
- Cancer Network. Reishi Mushroom. www.cancernetwork.com. Published: 2009-07-15.
- WebMD. Mushrooms: Health Benefits, Nutrients per Serving, Preparation Information, and More. www.webmd.com. Published: 2023-09-07.
- PubMed. Ganoderma lucidum (Reishi) an edible mushroom; a comprehensive and critical review of its nutritional, cosmeceutical, mycochemical, pharmacological…. pubmed.ncbi.nlm.nih.gov.
- PMC. Mushroom consumption and risk of total and site-specific cancer in two large US prospective cohorts. pmc.ncbi.nlm.nih.gov.
- PMC. Higher Mushroom Consumption Is Associated with Lower Risk of Cancer: A Systematic Review and Meta-Analysis of Observational Studies. pmc.ncbi.nlm.nih.gov.
- ScienceDirect. Mushroom Consumption Is Associated with Low Risk of Cancer: A Systematic Review and Meta-Analysis of Observation Studies. www.sciencedirect.com.
- Healthline. 6 Benefits of Reishi Mushroom (Plus Side Effects and Dosage). www.healthline.com. Published: 2025-05-01.
- WebMD. REISHI MUSHROOM: Overview, Uses, Side Effects, Precautions, Interactions, Dosing and Reviews. www.webmd.com. Published: 2023-05-29.
