June 06, 2022 5 min read

Reishi mushroom, also known as Ganoderma Lucidum, is a functional mushroom that grows in tropical climates around the world. With examples of its medicinal use dating back thousands of years and modern evidence to help us understand how to use Reishi's benefits to our advantage, the only question left is–are there Reishi side effects to be concerned about?

Luckily, Reishi may be a safe, natural therapeutic option for most consumers. There are some special circumstances, though, where you may need to work with your doctor to determine if you're at an increased risk of experiencing adverse Reishi reactions. Here's what you should know about possible Reishi side effects before you begin a new functional mushroom routine:

Table of Contents
Is Reishi Safe?
What are the Side Effects of Reishi?
Reishi Drug Interactions
Is Reishi Additive?
Who Shouldn’t Take Reishi?
Reishi Side Effects FAQs

Key Takeaways

  • Reishi side effects are rare and almost always mild.
  • You may be at a higher risk for side effects if you have a mushroom allergy or take certain medications.
  • You should talk to your doctor before taking Reishi if you have an immune system disorder, thyroid disorder, or have trouble with blood pressure or blood sugar.
  • Most people can take Reishi without any complications, but you need to choose a high quality supplement.

Is Reishi Safe?

A few small reishi mushrooms growing on a mossy hardwood tree

Reishi is thought to be safe for most people who do not have an allergy to mushrooms. In fact, it's an integral part of the regular diet for people around the world. Of course, in order to provide such a wide array of therapeutic benefits, Reishi contains a collection of bioactive compounds, like beta-glucans and triterpenes. In some cases, these bioactive compounds can over stimulate the system, which means some people could be at risk of an adverse reaction. It also contains a serious amount of fiber and minerals that, in rare cases, could cause digestive upset.

Although Reishi side effects are thought to be incredibly rare and have not yet been well studied, there are some possible adverse reactions to be aware of before adding Reishi to your daily wellness routine. Let's discuss:

What are the Side Effects of Reishi Mushrooms?

Based on anecdotal reports and what we know about medicinal mushrooms, Reishi side effects may include:

Nausea

In rare cases, some consumers have reported feeling nauseous after using Reishi mushrooms, especially when taken on an empty stomach.

Upset Stomach

Reishi's high fiber content could irritate the stomach of some consumers, especially those with bowel disorders or who are sensitive to fiber.

General symptoms of stomach upset may include gas, cramping, bloating, or diarrhea.

Allergic Reaction

Although it is rare, some people experience a mushroom allergy. It's also possible, although even more rare, that some people who do not have a mushroom allergy experience an allergic reaction after consuming Reishi. Understanding how to recognize the symptoms of an allergic reaction is crucial before trying new herbal supplements.

Symptoms of an allergic reaction to Reishi mushrooms may include:

  • Swelling of the lips, mouth, and airways
  • Difficulty breathing
  • Skin rashes or hives
  • Runny nose
  • Watery eyes
  • Nausea and vomiting
  • Stomach cramping
  • Bloating
  • Loose stools

Interactions With Other Supplements or Medications

In some cases, medicinal mushrooms like Reishi may interact with certain OTC and prescription medications, which could reduce their efficiency. We'll discuss this more below.

A bottle of prescription pills that may have adverse interactions with reishi mushroom

Reishi Drug Interactions

There is not much research regarding Reishi drug interactions, but it’s well documented that some functional mushrooms will interact with certain types of medications. You may be able to take Reishi alongside certain medications with a doctor's guidance and adjusted dosage.

Talk to your doctor before taking Reishi if you take one of the following type of medications:

  • Antidepressants
  • Anti-anxiety medications
  • Thyroid medications
  • Blood pressure medications
  • Diabetes medications

Is Reishi Addictive?

Nope! Reishi does not contain any habit forming compounds. It is not a hallucinogenic mushroom and therefore has very little potential for abuse or misuse.

Is Reishi Toxic for Your Liver?

Some sources report that taking Reishi daily for periods of time exceeding one year can have a negative impact on the liver. The evidence used to substantiate this claim is limited and more research is needed to understand the true liver-related risks. One animal study actually found that Reishi mushroom spores may help boost the regeneration of liver cells, which can improve the liver’s ability to detoxify the body.

Who Shouldn’t Take Reishi?

Most people can take Reishi without complication, and most of the side effects that could arise for healthy people are mild. However, some people may need to be wary about using certain functional mushroom formulations. Those who may be at an increased risk of Reishi side effects include:

  • Those with bleeding disorders
  • Diabetics
  • Those with immune system disorders
  • Those expecting surgery in the next two weeks
  • Anyone with a thyroid disorder
  • Anyone taking blood pressure medication
  • Those who are pregnant or breastfeeding
A bowl of dried reishi and a cup of reishi tea made by steeping the mushrooms shows two different dosing methods that can be used for daily doses.

Reishi Side Effects FAQ

Is Reishi safe to take daily?

For most people who do not have a mushroom allergy, Reishi is safe to take daily. In fact, daily dosing is the best way to experience the benefits of adaptogenic mushrooms like Reishi.

When should you not take reishi?

There is not a specific time of day where you shouldn't take Reishi. Of course, some people may need to avoid Reishi during certain circumstances, like while pregnant or breastfeeding, when taking certain medications, or before undergoing surgery.

Can reishi be toxic?

In general, no, Reishi is not toxic. Some evidence suggests that taking Reishi daily for extended periods of time could negatively impact the liver, but more evidence is needed to understand this side effect. However, research shows that it may be safe to take Reishi daily for at least one year without any adverse effects on the liver.

What happens when you take reishi?

Reishi mushroom has historically been used to support immune functions, promote relaxation, and calm the nervous system. The true extent of Reishi's benefits may be much greater, and advancing research aims to help us understand its potential for managing serious health conditions, like high blood pressure and high cholesterol.

Does reishi interact with any medications?

Some Medications may have adverse interactions with Reishi mushrooms. You should talk to your doctor about Reishi if you already take a daily medication, including antiplatelet, anticoagulant, antidepressants, or antihypertensive drugs.

Can pregnant women take Reishi mushrooms?

There are no known side effects of Reishi, but the safety of functional mushrooms for pregnant women has not been tested. We recommend talking to your doctor before using Reishi if you are pregnant or breastfeeding.


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