Reishi Mushroom: Benefits, Side Effects, Best Time to Take It & More

Reishi Mushroom

(Ganoderma lucidum)

Evidence: Very High
Possible Benefits: High
Safety: High

What is Reishi?

Ganoderma lucidum, also known as Reishi, is a type of mushroom with a long history of use as a traditional medicine in many places around the world. This mushroom is often used as a supplement for improving sleep quality and general well-being. This article is about the main benefits of Reishi mushroom, its potential side effects, the best time to take it, and more.

Possible benefits

All of the potential benefits mentioned below are dose-dependent. As with other adaptogenic mushrooms, there is a sweet-spot dose that allows you to get most of the benefits without causing meaningful side effects or tolerance buildup in the body. We will discuss the best dosing protocol later in this article.

Major benefits

Anti-cancer effects – Reishi has been shown to slow down the growth of colorectal cancer and may be able to suppress or reduce the growth of other types of cancer as well. This mushroom is also effective for reducing depression and anxiety related to many types of cancer.
Reduced fatigue – Reishi mushroom can reduce fatigue related to disease states. Whether or not it can influence fatigue caused by exercise or sleep deprivation is not yet clear.
Improved sleep quality – The mushroom can improve sleep quality when taken before bed, especially in people who experience restlessness at night.
Improved immune system – Reishi can increase natural killer cells by as much as 50%. Some other markers of immune health also seem to improve in most people taking the mushroom.

Minor benefits

Increased well-being – Subjective well-being increases in people with diseases where Reishi is able to reduce other symptoms of the disease.
Increased HDL cholesterol – This mushroom can increase HDL cholesterol levels by as much as 24% in people with hyperlipidemia. This effect doesn’t apply to healthy individuals.
Reduced triglycerides – Normal doses can reduce triglycerides in unhealthy people by about 8%. The supplement doesn’t seem to affect triglyceride levels in healthy people.
Improved blood sugar levels – Most mushrooms, including Reishi, can positively affect blood glucose levels because of their polysaccharide content. This potential benefit mainly applies to diabetics and people with unhealthy blood sugar levels.

Possible side effects

The side effects below are dose-dependent. The risk for them increases (often linearly but sometimes exponentially) as you increase the dose. Some of the side effects only apply to very high doses.

Nausea – This side effect is most common when people take the mushroom on an empty stomach.
Diarrhea – Reishi can act as a laxative and cause diarrhea at high doses (5-10 grams of extracts daily). Vitamin C can often prevent and alleviate this effect. Just like nausea, diarrhea caused by the supplement can usually be prevented by taking the mushroom with food.
Toxicity – As an adaptogenic mushroom, Reishi acts as a mild stressor on the body. That is usually a great thing as it allows your body to adapt to specific forms of stress and become more resilient. However, stressing the body too much can be counter-productive and cause multiple side effects, including toxicity. While acute toxicity is extremely rare, taking high amounts of this mushroom could lead to chronic toxicity and cause some health problems over time. To prevent chronic toxicity or the buildup of tolerance, it is best to stay below 10 grams of Reishi extracts a day unless you have a great reason to take more.
Contamination – If growing conditions are not properly controlled, Reishi can be contaminated with bacteria, molds, and other potentially harmful microorganisms. The mushroom can also be contaminated because of poor harvesting, processing, and packaging practices. Some growers also use fungicides, chemical compounds designed to kill or prevent the growth of other fungi. Many fungicides can have detrimental effects on human health. Choose the brand you get mushrooms and mushroom supplements from wisely.

Who should not take Reishi?

You should probably avoid taking the mushroom if you:

are allergic to Reishi or mushrooms in general
experience a severe adverse reaction after taking the mushroom
are pregnant or breastfeeding (while it may be safe to take the adaptogen during pregnancy or breastfeeding, it can act as a stressor and should likely be avoided during this period)
suffer from an autoimmune disease (adaptogenic mushrooms can stimulate the immune system, which can worsen symptoms of autoimmune diseases, such as lupus or multiple sclerosis)
are on a tight supplement budget (there are more cost-effective supplements on the market for most people)

Who will benefit the most?

You should consider taking the supplement if you:

are often restless at night
suffer from cancer
experience fatigue, anxiety, or depression related to an illness
have a high budget for supplements and are willing to experiment with a variety of them (Reishi appears safe and is unlikely to do more harm than good in most people)

How much Reishi should you take?

Because Reishi can be considered an adaptogenic mushroom, it acts as a mild hormetic stressor on the body, which allows your body to adapt and become more resilient in the long term.

As with other adaptogens, a higher dose does not necessarily lead to bigger benefits. Instead, there appears to be an inverted U-shaped dose-response pattern. In other words, you want to find a sweet-spot dose that allows you to get the benefits of Reishi mushroom without putting too much stress on the body or quickly causing the body to develop tolerance to the mushroom.

The sweet-spot dose typically ranges anywhere between 500 mg to 6 grams of a mushroom extract daily, which can be obtained from 5-60 grams of whole mushroom. This amount should provide most of the benefits without meaningful side effects.

The higher end of this range usually provides slightly more benefits in the short term. If you plan to take the mushroom for a longer time (multiple months or years), the lower end is probably a better way to go since you’d develop tolerance faster if you were to take higher doses.

While higher doses are generally safe, taking more than the sweet-spot dose daily would be counter-productive as your body would develop tolerance rather quickly. Additionally, very high doses can put too much stress on your system and cause some health problems if you take the supplement for a prolonged period.

Just like with most other adaptogens, it is best to cycle Reishi and stay off of it for about 2 days per week to reset your tolerance. This will allow you to keep getting the benefits in the long term.

Keep in mind that the effects of this mushroom are cumulative. Therefore, you must take it for at least 2-4 weeks to notice the benefits. But again, cycling the mushroom and not taking it at least twice a week is necessary to prevent tolerance in the long term.

Best time to take Reishi

The main bioactive compounds in Reishi are fat-soluble so to maximize the absorption, take this mushroom with a meal.

It is usually best to take the mushroom before bed because of its positive impact on sleep quality.

Reishi can cause nausea and stomach discomfort when taken on an empty stomach. If you keep experiencing these unpleasant effects even after one week of taking the supplement, it’s usually better to take the supplement with food.

Interactions

Vitamin C
Reishi can act as a laxative and cause diarrhea at high doses (5-10 grams of extracts daily). Vitamin C can often prevent and alleviate this effect.

Where to buy Reishi mushroom?

Amazon is the best option for ordering Reishi and other mushroom supplements in most countries. They offer some very affordable products backed by many positive reviews. Also, you can choose from a wide range of brands without having to search through other markets on the internet.

Some brands display the dosage per serving instead of per pill or capsule. Therefore, you may accidentally buy something less potent than you intended. Do not fall for this marketing trick.

FAQ

As with most other mushrooms and mushroom supplements, it is best to cycle Reishi and stay off of it for about 2 days per week to reset your tolerance back to baseline. This will keep your body sensitive to the mushroom and allow you to keep getting the benefits in the long term.

Yes. This mushroom should not impact sleep quality in any negative way and will likely improve your sleep quality.

Either way, take this mushroom with food to maximize the absorption of its fat-soluble components.

This mushroom should not become harmful once it exceeds the expiration date but it can lose potency over time.

Keep the supplement in a cold, dark, and dry place, and it should remain just as potent for many months or even years.

As an adaptogen, Reishi acts as a mild stressor on the body. This is usually a great thing as it allows your body to adapt to specific forms of stress and become more resilient. However, putting too much stress on the body can be counter-productive and cause multiple side effects, including toxicity. While acute toxicity is extremely rare, taking high amounts of this mushroom could lead to chronic toxicity and cause some health problems over time. To prevent chronic toxicity or the buildup of tolerance, it is best to stay below 10 grams of extracts a day unless you have a great reason to take more.

This mushroom consists of many bioactive compounds, each of which has a different half-life in the body. Some of these components should be fully metabolized within hours while some of them will stay in the body for a few days.

The effects of this mushroom are cumulative. Therefore, you must take it for at least 2-4 weeks to notice the benefits. But again, cycling the mushroom and not taking it at least twice a week is necessary to prevent tolerance in the long term.

Yes, Reishi mushroom is vegan-friendly. If you buy the mushroom in a capsulated form, beware that the capsules often contain animal-based gelatin. Instead, find a brand that puts its products into cellulose capsules.

Reishi should not break a fast unless you take a very high dose at once. If you practice time-restricted eating, take this mushroom during your eating window so it doesn’t break your fast.

References

Most of the information provided in this guide is supported by scientific research that can be found and verified in the PubMed medical library. We highly encourage you to use the library to verify anything said in this article. We excluded from consideration studies that are either confounded or have a high conflict of interest.

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