Mushroom Supplement Side Effects: Types, Risks, and Benefits

Mushroom supplements are the best way to take advantage of medicinal mushroom benefits. Supplements offer a concentrated dose of beta-glucans and other bioactive compounds, so they have a leg up on whole mushrooms, tinctures, and other dosing forms. 

The question is–what are mushroom supplement side effects? And do the potential side effects outweigh the potential benefits?

You’ll be happy to know that mushrooms supplements rarely result in unwanted side effects, and the most common risks involve mushroom allergies and drug interactions. Still, before you dive into the world of medicinal mushrooms, let’s explore the possible side effects of mushroom supplements to gain a more comprehensive understanding of their risks and benefits.

Mushroom supplements are generally considered safe for most individuals when used responsibly and under a doctor’s guidance. However,  it is crucial to be aware of potential side effects that may occur in certain circumstances. 

Understanding potential mushroom supplement side effects can help you recognize early warning signs and catch reactions early. As always, it is recommended to consult with a healthcare professional before starting any new dietary supplement regimen.

If you decide to incorporate medicinal mushroom supplements into your wellness routine, here are the most common side effects to look out for:

The most common side effect associated with mushroom supplements is allergic reaction. Individuals with known allergies to mushrooms should exercise caution when consuming mushroom supplements. 

Allergic reactions may manifest as skin rashes, itching, swelling, or difficulty breathing. It is essential to read the labels of mushroom supplements carefully and choose those that have undergone rigorous quality testing to minimize the risk of contamination with other fungi.

Some people may experience digestive issues such as bloating, gas, or mild stomach discomfort when taking mushroom supplements. This can be attributed to the high fiber content present in certain mushrooms–though it may not happen as often with extract products where much of the fiber is stripped away. Starting with a lower dosage and gradually increasing it can also help mitigate these effects.

Certain mushroom species, such as Reishi and Cordyceps, may have potential blood-thinning effects. These mushrooms contain compounds that can inhibit platelet aggregation and interfere with blood clotting mechanisms. While this may be beneficial for individuals with certain cardiovascular conditions, such as high blood pressure or clotting disorders, it may pose a risk for those already taking blood-thinning medications. 

It is crucial for those taking bloodthinners to consult their doctor before incorporating mushroom supplements into their regimen to avoid potential life-threatening interactions. 

Many medicinal mushrooms interact with immune system function, which can be useful for those who need an immune boost. However, it may further dysregulate immune function in those with an overactive immune system, or could interact with the medications used for other immune system disorders. 

People with autoimmune disorders, such as rheumatoid arthritis or lupus, should exercise caution and speak with their healthcare provider before using mushroom supplements. 

Mushroom supplements, like any dietary supplements, have the potential to interact with certain medications. For instance, Cordyceps may interact with certain immunosuppressive drugs, while Reishi may interact with anticoagulants or antiplatelet medications. It is vital to inform healthcare providers about any mushroom supplements being used to ensure the safety and efficacy of concurrent medications.

When choosing mushroom supplements, it is crucial to select reputable brands that adhere to strict quality standards. Poorly manufactured or contaminated supplements may pose risks such as bacterial or fungal contamination, heavy metal toxicity, or improper dosing. 

Look for products that have undergone third-party testing and carry certifications from reputable organizations to ensure quality and safety. In order to reap significant benefits, you should also look for formulas that contain a beta-glucan content of 20% or more. 

Mushroom supplements usually refer to powdered or encapsulated versions of dried medicinal mushrooms. Mushrooms supplements come in two forms, and they are each substantially different. Take a look:

Whole mushroom powder is exactly what it sounds like–a dried, ground version of the whole mushroom. This type of product is great for dietary purposes because it contains all of the fiber, vitamins, and minerals found in the original mushroom material. 

However, whole mushroom powder has one distinct caveat–bioactive compounds such as beta-glucans and terpenoids are locked away in the chitin, the polymer that makes up the mushroom’s cell walls. The human digestive system isn’t great at breaking down chitin, which means many of these healthful compounds pass through the digestive tract and are not absorbed. 

If you want to take advantage of the medicinal effects of functional mushrooms, you may want to choose a mushroom extract. 

Mushrooms extract, on the other hand, is a concentrated version of the beneficial, bioactive compounds found in the mushroom material. Most often, mushroom extract is made via hot water extraction. Hot water is effective at melting away cheating and unlocking beta-glucans, the bioactive polysaccharides that are linked to most of mushroom’s health benefits. Then, the water can be evaporated away, and only a powdered beta-glucan-rich mushroom concentrate is left behind. 

Either process can be used to make mushroom supplements from all sorts of medicinal mushrooms, and the side effects associated with a particular formula will vary based on the types of mushrooms used. 

You may also want to consider the difference between mushroom supplements made from mushrooms mycelium and those made from fruiting bodies, which have a more concentrated amount of beta-glucans. 

Let’s take a look at the most popular types of mushroom supplements: 

Before delving into the side effects, let's understand the different types of mushroom supplements and their key properties.

Lion's Mane (Hericium erinaceus) is known for its potential cognitive benefits and is often used to support brain health. It is rich in compounds called erinacines and hericenones, which are believed to promote the growth of nerve cells and enhance cognitive function.

A study published in the International Journal of Molecular Sciences found that lion's mane extract improved the function of hippocampal neurons, which play a crucial role in learning and memory. Lion's mane is also rich in antioxidants and anti-inflammatory compounds, which can protect the brain from damage caused by oxidative stress and inflammation. More evidence suggest that Lion’s Mane may help to stimulate nerve growth and speed brain recovery time after injury.

Thanks to its purported brain-boosting benefits, lion's mane coffee is becoming a popular alternative to traditional coffee beverages as the ultimate morning pick-me-up, but you can also find a variety of lion’s mane powders and capsules. 

The optimal dosage of lion's mane extract is not yet clear. However, most studies have used doses ranging from 500 to 3000 mg per day.

Tremella (Tremella fuciformis) is a white, jelly-like mushroom with potential benefits for skin health. It is rich in polysaccharides that may help improve hydration and elasticity, making it a popular ingredient in skincare products.

According to some sources, the mushroom contains high levels of hyaluronic acid, which is a compound that helps the skin retain moisture and stay hydrated. A 2000 study in the International Journal of Medicinal Mushrooms also reports that Tremella has strong anti-inflammatory effects and many other potential benefits. 

A 2018 study showed similar results, stating that Tremella prevented the development and spread of inflammation in the body. According to this study, that may make it a useful treatment option for inflammatory conditions like heart disease, obesity, and more, and some researchers theorize that this could add to its anti-aging benefits. 

The optimal dosage of tremella extract is not yet clear. However, most studies have used doses ranging from 1 to 3 grams per day.

Shiitake (Lentinula edodes) mushrooms are highly valued in Asian cuisine for their unique taste and potential health benefits. They contain compounds like lentinan, which has been studied for its immune-boosting properties. Among potential cancer fighting and cardiovascular benefits, shiitake mushrooms also have multiple direct links to improved gut health. 

For instance, a 2015 study published in the Journal of the American College of Nutrition followed 52 healthy males and females between the ages of 21–41 years through a four week trial to determine if daily consumption of shiitake would improve immune function. The study concluded that consuming shiitake regularly improved gut immunity and cell effector function, or the ability of cells to respond to immune stimuli. There was also a notable reduction of inflammation due to shiitake mushroom consumption.

Further studies indicate that the fiber found in shiitake may reduce inflammation in a way that supports digestive and gut health. In fact, it's known as one of the best mushrooms for gut health. 

Most sources suggest taking 1,000 millgrams of shiitake extract daily. However, when shiitake is used for gut-supporting purposes, 2-3 whole shiitake mushrooms daily may be the better choice. 

Maitake (Grifola frondosa) mushrooms are often called "Hen of the Woods" due to their feather-like appearance. They are believed to have immune-supporting properties and are rich in beta-glucans, polysaccharides known for their potential health benefits.

Research suggests that these polysaccharides may support cellular immunity to help prevent illness and infections. A study published in 2009 confirmed similar results on breast cancer patients. In fact, one study published in 2012 found that there may be a duality to Maitake’s immunity enhancing effects–Maitake extract was found to be effective in killing human cancer cells and also increasing the effectiveness of cancer-fighting proteins taken at the same time.

The optimal dosage of maitake extract is not yet clear. However, most studies have used doses ranging from 1 to 9 grams of extract per day.

Reishi (Ganoderma lucidum) is a woody mushroom that has been used for centuries in traditional Chinese medicine. It is often referred to as the "mushroom of immortality" and is believed to promote overall well-being, support the immune system, and reduce stress. Some cultures today use Reishi as an immune system stimulant for patients with certain immune-system disorders, like HIV or cancer.

A 2014 study highlighted Reishi as one of four functional mushrooms with prominent immune stimulating effects. Another study highlights Reishi’s potential adaptogenic effects, suggesting that it may improve the pain and mood changes surrounding a condition caused by chronic exhaustion. In a survey of nutritional habits, those who regularly consumed mushrooms, including reishi, reported significantly lower rates of depression.

 Various smaller trials have verified similar results, claiming that consuming more mushrooms in general may help reduce both depression and anxiety.

The optimal dosage of reishi extract is not yet clear. However, most studies have used doses ranging from 1 to 9 grams per day.

Chaga (Inonotus obliquus) is a mushroom that has been traditionally used in Russian and Chinese folk medicine for its anti-cancer properties. This mushroom contains betulinic acid, which is a compound that has been shown to induce apoptosis (programmed cell death) in cancer cells. 

One animal study found that Chaga supplementation reduced tumor size by 60%. Another study found that Chaga tea could prevent and slow the proliferation of human colon cancer cells. In a test-tube study, chaga extract prevented cancer growth in human liver cells. Various other studies have observed Chaga’s potential to kill other types of cancer cells, like lung, skin, colon, and prostate cancer cells.

Chaga research is limited and more evidence is needed to fully understand chaga’s immune-enhancing and cancer-fighting potential, but many people use it in their illness-prevention regimen with positive results. 

The optimal dosage of chaga extract is not yet clear. However, most studies have used doses ranging from 1 to 9 grams per day.

Cordyceps (Cordyceps sinensis) is a fungus that grows on caterpillar larvae in the high-altitude regions of China, Tibet, and Nepal. This mushroom has been traditionally used as an energy booster and is often classified as a nootropic mushroom, and recent research has confirmed its ability to increase energy and reduce fatigue. 

In a study published in the Journal of Alternative and Complementary Medicine, participants who consumed cordyceps extract for 12 weeks reported a significant improvement in their exercise performance and endurance compared to the placebo group. Another study published in 2017 echoed these results. Participants experienced an increase in tolerance to high-intensity workouts after supplementing with Cordyceps for only one and three weeks. 

Cordyceps also has anti-inflammatory and antioxidant properties, which can help reduce muscle damage and promote recovery after exercise.

The optimal dosage of cordyceps extract is not yet clear. However, most studies have used doses ranging from 1 to 3 grams per day of cordyceps extract. 

While the potential side effects of mushroom supplements should not be overlooked, it is important to note that these products also offer a range of potential health benefits. The key lies in using them responsiblyand taking appropriate precautions. Here’s how to get started:

Before incorporating any mushroom supplement into your routine, consult with your healthcare professional who can assess your specific health needs, medical history, and any potential contraindications or interactions with medications you may be taking.

To minimize the risk of adverse effects, it is advisable to start with small dosages when beginning any new mushroom supplement. This allows the body to gently adjust to your new dosage routine. Plus, it allows you to easily determine if you have any negative reaction to the supplements without the side effects being severe. 

Over time, you may gradually increase the dosage as tolerated and as recommended by your doctor. 

One of the most significant risks associated with any supplement is the risk of getting your hands on a poor quality product. Supplements are not regulated as well as pharmaceuticals in the U.S., so it’s up to the consumer to vet produces for quality markers before they buy. 

Choose mushroom supplements from reputable manufacturers that follow good manufacturing practices (GMP) and undergo rigorous testing for quality and purity. A mushroom extract product should always list the beta-glucan content, which should be 20% or more for high-quality products. 

Mushroom supplements offer a wide range of potential health benefits, but it is essential to be aware of possible side effects and exercise caution when using them. Allergies, gastrointestinal discomfort, blood-thinning effects, interactions with medications, and considerations for individuals with autoimmune disorders are some of the key factors to be mindful of. 

Fortunately, the risk of side effects is low for those who do not have a mushroom allergy and do not take conflicting medications. Consulting with your doctor, starting with low doses, and choosing high-quality products can mediate this risk even further. 

The benefits of a high-quality medicinal mushroom product may outweigh the risks for most people. You may also consider choosing a mushroom stack, or a combination mushroom product that allows you to reap the benefits of multiple functional mushrooms at once.