Traditional Chinese medicine recorded a cornucopia of herbs, roots, and extracts that could improve cognitive function. Reishi mushroom (also known as lingzi mushroom) is one of their favorite fungi often considered the “mushroom of immortality” . Despite the obviously exaggerated claims regarding immortality, modern science has validated many of the features of this medicinal mushroom.
Evidence on reishi mushroom show it is most powerful as a immune booster  and has applications fighting tumors and cancers in animal and human studies . The reishi mushroom is also neuroprotective and can even support the growth of neurogenesis through chemicals like brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) .
The results from over 200 different studies prove reishi is a powerful medicinal mushroom that is gaining momentum and popularity in western use. Studies of reishi side effects have shown very few problems and is considered well-tolerated and safe.
Also Known As
Reishi, Lingzhi, Yeongji, Mannamtake, 10, 000 years mushroom, Mushroom of Immortality, Antlered Reishi, Rokkaku-Reishi, Ganoderma spores
Editors’ Thoughts on Reishi
Reishi mushroom is one of the few medicinal mushrooms that I have consumed myself. I mix it together with mucuna pruriens and cacao powder in smoothies because I like it so much.
The anti-anxiety effects aren’t as strong as some of the extracts, but they definitely make me feel a lot better. I don’t necessarily feel any immune boosting properties, but it is definitely a situation of “just in case” given the amount of research about the mushroom that I trust.
If you’ve got the money to spend on your immune system, reishi mushroom is definitely a good bet. It isn’t a first line nootropic to improve your cognitive performance, but I like taking immune boosters that will prevent me from having debilitating illnesses that take me away from work.
Mansal Denton, Nootropedia Editor
History of Reishi
There is a reason the traditional Chinese medicinal experts considered this mushroom to be the “God of Fungi”. It was used by the upper class in China as a catch all substance that could make a big difference in the general health of users.
Used for thousands of years, the mushroom spread to Korea and Japan by way of Chinese kingdoms and eventually made it to the west in the past couple hundred years. It wasn’t until recently that traditional Chinese medicine has grown in popularity exponentially .
Benefits of Reishi Mushroom
The benefits of reishi mushroom are often difficult to quantify, but there are advantages for anxiety, mood, and wellbeing. One study on well being showed that 5.4 grams of reishi per day for 8 weeks had a significant improvement in well being and it also reduced fatigue . Another study showed a reduction of anxiety in female cancer patients from a total of 3 grams per day over 4 weeks .
Of course cancer patients don’t only see mood changes with reishi mushroom. The traditional Chinese touted this fungus as one of the most powerful immune boosters that they had. Reishi often fights tumors through an increased immune response. Treatment of 5.4 grams per day led advanced cancer patients to improve immune parameters and reduce signs of inflammation .
Reishi is so useful as an anti-cancer supplement that it was used by 58.8% of Chinese breast cancer survivors of their own free will . This mushroom is powerful for anti-cancer benefits because the bioactive ingredients increase natural killer (NK) cells in the immune system, which kill tumor and cancer cells before they create too many health problems .
For the brain, one of the main reishi benefits is neurogenesis. The fungus helps enhance the quantity of brain chemicals NGF and BDNF , which are both associated with enhancing neurological connection and mental performance.
Finally, reishi mushroom is often used in traditional medicine as a sedative or sleep agent. It can help those who are suffering from insomnia  and is used to increase delta and other wave activity in the brain.
Side Effects of Reishi Mushroom
As a medicinal mushroom, there are relatively few side effects of reishi. Depending on your desired use, the aforementioned sleepiness might be a negative side effect. While some people suffering from insomnia love these effects, if you are consuming this for immune system benefits and don’t wish to fall asleep, this might be something to consider.
Otherwise, there are a few mild and rare side effects of reishi such as loose stools and gastrointestinal issues. Someone who is not used to high doses of mushroom extract might have this at first and then become more accustomed to using it.
Studies on usage show doses of 1.44 grams of extract for a month did not show any toxicological signs in the body . Other case studies have not shown any conclusive evidence that this mushroom is to blame for side effects that are harmful to humans.
Reishi mushroom (along with most fungi) is around 90% water and the extract you must consume is essentially the dried mushroom. For the reishi dosage, you will find a range of doses from 1.44 grams – 5.2 grams of reishi extract. The higher dose range is more popular, but you may want to start small and increase as your system acclimates to it.
How and Where to Buy Reishi
Reishi mushroom is very popular in traditional Chinese medicine, but in the western world might be slightly harder to find. Some health food grocery stores will have reishi mushroom for sale, but in general you will need to look to the internet for the best and most affordable sources of the fungi.
The raw mushroom powder is about 10 times that of the extract. If you’re looking for 1.44 grams of extract, that will be 14.4 grams of raw mushroom powder. The higher dose range is 52 grams of powder. Keep this in mind when you are buying as there is a big difference between the reishi extract and reishi bulk powder.
Selected Community Experiences
“I started taking Reishi Mushroom a few weeks ago after a few years off and noticed very perceptible brain fog setting in after a week or two. I took a few days off my other stack and tried Reishi alone and noted that the brain fog intensified. Today is my second day off of Reishi and my brain fog has finally subsided.”  – Schneidercarrot
- References (Click to Expand)
- Other Scientific Resources (Click to Expand)