Reishi: Benefits, Uses and Safety of the Medicinal Mushroom

Ganoderma lucidum

What is reishi?

Reishi, also known as lingzhi or lacquered polypore, is one of the best-known medicinal mushrooms in traditional Chinese and Japanese medicine, where it has been used for more than 2,000 years. Its old nickname, “mushroom of immortality”, reflects how highly it was valued for longevity and vitality.

Reishi is not a culinary mushroom. It is woody, tough and bitter, so it is used as a tea, powder, extract or capsule rather than in cooking. It is usually classed as an adaptogen – a substance thought to help the body cope with stress – and is mainly studied for its effects on the immune system, sleep and inflammation.

What does reishi contain?

Reishi’s effects are attributed mainly to its polysaccharides and triterpenes. Approximate values for the dried mushroom:

It also contains small amounts of potassium, magnesium, zinc and selenium. Since reishi is taken in gram quantities, these nutrients play only a minor role; the content of active compounds varies greatly between products.

How might it support health?

Most research on reishi comes from laboratory and animal studies; human studies are fewer and often small. Based on what is known so far, reishi may:

• modulate the immune system,
• have anti-inflammatory and antioxidant effects,
• support relaxation and sleep,
• slightly lower blood sugar and blood lipids (the results in humans are inconsistent),
• protect the liver (mainly shown in animal studies).

It is traditionally used for:

• stress and exhaustion,
• poor sleep,
• frequent infections,
• allergies,
• general vitality in older age.

There is currently no reliable evidence that reishi treats ADHD, diabetes or leaky gut. If you have one of these conditions, reishi can at most be a supplement to medical care – not a substitute.

Reishi and the nervous system

In animal studies, reishi extracts have shown calming and sleep-promoting effects, possibly via GABA-related mechanisms, as well as protective effects on nerve cells. A few small human studies suggest it may reduce fatigue and improve well-being, for example in people with neurasthenia (a condition of chronic exhaustion).

Whether reishi improves concentration, mood or memory in healthy people has not been demonstrated. Many people use it as a calming evening drink – which may be worth trying, but expectations should be modest.

Other uses

In traditional medicine, reishi is used to:

• support the liver,
• strengthen immune defense during infections,
• accompany cancer treatment.

Reishi is popular as a complementary treatment for cancer in Asia. A Cochrane review found some evidence that it may improve immune parameters and quality of life when combined with conventional treatment, but the studies were of low quality, and it found no evidence that reishi prolongs survival. It should never replace cancer treatment, and it should only be used during chemotherapy in consultation with the oncology team.

Reishi extracts are also used in skincare products for their antioxidant properties.

Did you know?

In ancient China and Japan, wild reishi was so rare that it was reserved for emperors and the nobility. It appears in countless paintings, carvings and textiles as a symbol of long life and good fortune. Today almost all reishi is cultivated, on logs or substrate.

How to use reishi

Reishi is typically taken regularly over several weeks; any effects develop gradually.

Common forms and doses:

• Powdered extract: 1–2 g a day
• Tincture: follow the manufacturer’s instructions
• Tea or decoction: simmer 2–5 g of dried mushroom in water for 30–60 minutes
• Capsules: preferably standardized extracts with a stated beta-glucan content

Many people take reishi in the evening because of its calming reputation. There is no proven need for breaks, but some herbalists recommend cycles of six to eight weeks.

When choosing a product, look for extracts from the fruiting body with a stated beta-glucan and triterpene content and independent laboratory testing. Products made mainly from mycelium grown on grain often contain a lot of starch.

Combining reishi with other mushrooms and herbs

Reishi is often combined with:

• Ashwagandha – traditionally used for stress and sleep
• Lion’s mane – studied for cognitive function and nerve health
• Chaga – rich in antioxidants
• Cordyceps – traditionally used for energy and endurance

There are hardly any studies on such combinations, and every additional product increases the risk of side effects and interactions.

Who should be careful?

Reishi is well tolerated by most people in usual doses. Possible side effects include a dry mouth, digestive upset, dizziness and skin rashes. Rare cases of liver damage have been reported, particularly with powdered products.

Caution is advised for:

• people with autoimmune conditions or on immunosuppressive medication,
• people taking blood thinners (e.g. warfarin) or with bleeding disorders – reishi may increase the risk of bleeding; stop taking it two weeks before surgery,
• people taking medication for high blood pressure or diabetes – reishi can lower both,
• people with low blood pressure,
• pregnant and breastfeeding women – there is not enough safety data.

Talk to your doctor before taking reishi, especially if you take medication or have a chronic condition.

Recipe: reishi and cacao evening drink

A warm drink for winding down in the evening.

Ingredients:
1 tsp reishi powder
1 tsp raw cacao
1 cup plant-based milk (almond, oat, coconut)
1/4 tsp cinnamon
Pinch of cardamom
1 tsp honey (optional)

Instructions:
Warm the milk gently. Stir in the reishi, cacao, cinnamon and cardamom until dissolved. Add honey if you like and drink slowly.

What is reishi traditionally used for?

Reishi is traditionally used, and in some cases being researched, for:

Stress and exhaustion
Sleep problems
Frequent infections
Allergies
Chronic fatigue
Supportive care during cancer treatment (only in consultation with your doctor)
Blood sugar and blood lipids (evidence inconsistent)
Liver health
Skin care

In summary

Reishi is a traditional medicinal mushroom with interesting effects on the immune system, sleep and inflammation in laboratory and animal studies. The evidence in humans is still limited. If you want to try it, choose a high-quality extract, start with a low dose and check for interactions with your medication beforehand.

Disclaimer

The content provided here is for informational and educational purposes only. It does not constitute medical advice, diagnosis, or treatment. Always consult with your doctor or a qualified health professional before making any changes to your diet, supplement routine, or lifestyle — especially if you are pregnant, breastfeeding, taking medications, or managing a chronic condition.