Reishi Mushroom: Benefits, Side Effects & Dosage
You’re probably here because you’ve heard all about the magical fungi called Reishi, and you want to see for yourself if it's as great as people say.
Reishi mushroom is an adaptogenic mushroom that has been around for over 2000 years — with good reason. This mushroom is said to have numerous health and healing properties that no one would like to miss out on. But that doesn’t mean it’s free from side effects.
What Is Reishi Mushroom?
Reishi mushroom belongs to a class of mushrooms known as adaptogens. Adaptogens are herbs, roots, and mushrooms traditionally used in Chinese and Ayurvedic medicine to help the body adapt to stress.
Reishi mushroom (Ganoderma lucidum) is a reddish-brown, woody fungus with a shiny, varnished appearance and a bitter taste. It grows on dead or decaying hardwood trees.
In Chinese medicine, Reishi has long been used to enhance the immune system, reduce inflammation, and promote overall health and wellness — earning it the nickname “the mushroom of immortality.”
This mushroom contains a variety of bioactive compounds such as polysaccharides, triterpenes, and antioxidants, which are believed to contribute to its therapeutic properties.
Reishi mushroom is a fungus that grows on trees or decaying hardwood.
Is Reishi Mushroom Legal in the UK?
Yes, Reishi mushroom is legal in the UK. It’s considered a food supplement, doesn’t contain psychoactive ingredients, and can be sold in health food stores and online retailers.
However, it’s important to note that any health claims made about Reishi mushrooms or other food supplements must comply with EU regulations. These prohibit promoting claims not supported by scientific evidence.
What Are the Benefits of Reishi?
Reishi mushroom has remained popular for centuries due to its believed health benefits — from boosting the immune system to potentially fighting off cancer.
Although some claims still require more research, many people use Reishi for its potential therapeutic effects.
Reishi Alleviates Stress
Reishi mushrooms contain adaptogens, which can help the body regulate its response to physical, chemical, and biological stressors. When stressed, the body activates the hypothalamic-pituitary-adrenal (HPA) axis, releasing stress hormones like cortisol and adrenaline.
Reishi may help regulate the HPA axis and reduce stress hormone release, potentially lowering stress and anxiety levels.
In one study, participants experienced less anxiety and depression after taking Reishi for about 48 weeks. They also reported reduced fatigue and improved quality of life.
Read more: Reishi mushroom for sleep
Reishi Boosts the Immune System
One of the most studied benefits of Reishi is its ability to support the immune system. Its bioactive compounds are said to have immunomodulatory properties — meaning they can either stimulate or regulate immune activity.
1. Activation of Immune Cells
Reishi mushrooms contain beta-glucans — complex polysaccharides that bind to immune cells like macrophages and natural killer (NK) cells, activating them to eliminate bacteria, viruses, and cancer cells.
Research in cancer patients found that Reishi mushroom increased the activity of natural killer cells.
2. Modulation of Cytokines
Cytokines are proteins that act as messengers in the immune system. Reishi may help regulate cytokine production, promoting a balanced immune response.
3. Stimulation of Antibody Production
Reishi mushrooms are believed to stimulate immunoglobulin (antibody) production, helping the body recognise and fight foreign invaders.
Reishi Possesses Anticancer Properties
Reishi is often studied for its potential anticancer effects, though more human research is needed. In a study of over 4,000 breast cancer survivors, 59% reported consuming Reishi mushrooms.
Laboratory studies show Reishi extracts can trigger apoptosis (programmed cell death) in cancer cells and may also inhibit angiogenesis (formation of new blood vessels that feed tumours).
Always speak to a healthcare provider before taking Reishi if you’re undergoing cancer treatment.
Reishi as an Antioxidant
Reishi mushrooms are also believed to have antioxidant properties, helping protect the body’s cells from oxidative stress — a process that contributes to ageing and chronic diseases.
They may enhance the activity of antioxidant enzymes like superoxide dismutase (SOD) and catalase, which neutralise free radicals and reactive oxygen species (ROS).
Reishi’s anti-inflammatory effects may also contribute to its antioxidant potential, although more research is still needed.
What Are the Side Effects of Reishi?
Reishi mushrooms are generally considered safe for most people when consumed as food or supplements. However, like all natural remedies, they may cause side effects in some individuals — especially at higher doses.
Possible Side Effects Include:
- Allergic reactions: Some may experience skin rashes, itching, swelling, or difficulty breathing.
- Gastrointestinal distress: High doses may cause nausea, diarrhoea, bloating, or stomach discomfort.
- Blood thinning: Reishi may increase bleeding risk for those on anticoagulants.
- Low blood pressure: Beneficial for hypertension but can be risky for those with already low blood pressure.
Certain groups — such as pregnant or breastfeeding women, people with blood disorders, or those on medication — should avoid Reishi unless advised otherwise by a doctor.
How Do I Use Reishi Mushrooms?
Reishi mushrooms can be consumed in various forms depending on your preference. Below are the most common ways to take them:
Reishi Mushroom Powder
Dried Reishi mushrooms can be ground into a fine powder and added to smoothies, juices, or coffee for an easy daily boost.
Reishi Mushroom Tea
Reishi tea is one of the most traditional ways to consume this mushroom. Simmer dried Reishi in water for about 30 minutes, then strain and add honey or lemon to taste.
Reishi Mushroom Tincture
These are concentrated liquid extracts made by soaking mushrooms in alcohol and water for several weeks. They can be taken orally — usually diluted in water.
Reishi as a Culinary Ingredient
Fresh or dried Reishi can be added to soups, broths, and stews. Its bitter flavour pairs well with savoury dishes and adds a nutritional boost.
Reishi Mushroom Capsules or Tablets
Reishi supplements are also available in capsule or tablet form — a convenient option for consistent dosing. Always follow the manufacturer’s recommended dosage or your healthcare provider’s advice.
Reishi mushrooms can be dried and turned into powders, teas, tinctures, or capsules.
What Is the Ideal Reishi Mushroom Dosage?
There’s no single “ideal” dosage for Reishi mushrooms — it depends on your age, health status, and the form of Reishi you’re using.
However, general guidance suggests:
- 1–6 grams of dried Reishi mushroom per day
- 0.5–2 mL of Reishi tincture per day
Higher doses (25–100 grams) may be used if consuming the raw mushroom itself — but always consult a healthcare provider or herbalist before using Reishi, especially if you have medical conditions or are on medication.
How Long Does It Take for Reishi Mushroom to Work?
Like dosage, the time it takes for Reishi to work depends on factors such as your health status, dosage, and form of the mushroom.
Some people report benefits within a few days, while for others, it may take several weeks or months to notice significant changes.
Final Words
While Reishi might sound like a magical cure-all, there’s still much research to be done to confirm all of its potential benefits and risks.
Current evidence suggests Reishi may support immune health, reduce stress, and provide antioxidant protection. However, supplements should never replace a healthy diet or lifestyle.
If you decide to give Reishi a try, start with a low dose and gradually increase it as needed — and always consult your doctor if you’re taking medication or managing a health condition.
Frequently asked questions
Is Reishi legal in the UK?
Yes. It’s sold as a food supplement (non-psychoactive). Health claims must comply with evidence-based regulations.
What are the main benefits of Reishi?
People use Reishi for immune support, stress balance, antioxidant activity and general wellbeing, though more human research is needed.
What side effects should I watch for?
Possible reactions include GI upset, allergies, blood-thinning effects, and lowered blood pressure — particularly at higher doses.
How should I take Reishi?
Common forms include powders, teas, tinctures, capsules/tablets, and culinary use in broths/soups. Follow product directions.
What’s a typical Reishi dosage?
Often cited ranges are 1–6 g dried mushroom daily or 0.5–2 mL tincture daily. Consult a clinician for personal guidance.
How long before I notice effects?
Some notice changes within days; for others it may take weeks to months, depending on dose, form and individual factors.
Who should avoid Reishi?
Those pregnant/breastfeeding, with bleeding disorders, low blood pressure, or on medicines (e.g., anticoagulants) should seek medical advice first.
