Functional Mushrooms 101: Are They Bull-Shiitake or Legit?


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Functional mushrooms, also known as medicinal, nootropic, or adaptogenic mushrooms, are forms of fungi that offer health benefits beyond their nutritional value.

Rooted in thousands of years of ancient medicine, these mushrooms may support enhanced mood, sleep, immunity, digestion, cognitive function, skin health, and more. Recent research even suggests that certain functional mushrooms may offer cancer-fighting benefits.  

Some of the most widely-known functional mushroom varieties are lion’s mane, reishi, chaga, turkey tail, and cordyceps. While exploring the vast world of functional mushrooms, it’s important to remember that they haven’t yet been FDA-approved to treat any medical condition and they may trigger side effects in some individuals, like allergy symptoms, dizziness, nausea, and upset stomach. People with underlying medical conditions should check with their physicians before using functional mushrooms. 

Read on for a comprehensive guide to functional mushrooms, including their benefits, varieties, potential side effects, and more.  

Definition of Functional Mushrooms

Functional mushrooms are mushroom species that provide health benefits, such as immune support, that are beyond their nutritional value.

What Are Functional Mushrooms?

Functional mushrooms are mushrooms that provide medicinal properties and promote greater overall health. Recent clinical research indicates that certain mushrooms may exhibit an expansive range of pharmacological properties, including:

  • Antioxidant and anti-inflammatory properties
  • Antiviral and antifungal properties to help reduce infection
  • Antiallergic properties, meaning that they can help curb allergy symptoms
  • Immunomodulating properties to enhance immune function
  • Antidepressive properties
  • Neuroprotective properties to protect the nervous system from damage and degeneration
  • Hypotensive properties to lower blood pressure
  • Antidiabetic properties to help manage blood sugar levels
  • Antihyperlipidemic properties to help prevent high cholesterol levels
  • The capacity to protect against kidney, liver, and bone damage
what are functional mushrooms

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As functional mushrooms become more mainstream in the wellness industry, they can now be found in several different forms, including:

You can also consume functional mushrooms in their natural mushroom form, although they may be trickier to incorporate into your daily routine. 

While functional mushrooms are considered a type of herbal remedy, their benefits surpass herbs that provide purely nutritional value. Beyond optimizing your nutrient levels, medicinal mushrooms may support various bodily processes for more notable wellness benefits. They also differ from psychedelic mushrooms in that they don’t produce psychedelic effects, such as hallucinations. 

Functional Mushrooms vs. Adaptogenic Mushrooms

Adaptogenic mushrooms help your body respond more effectively to stress. Some, but not all, functional mushrooms offer adaptogenic properties, meaning that adaptogenic mushrooms are a type of functional mushroom.

What Do Functional Mushrooms Do for You?

How functional mushrooms affect the brain and body depends on their bioactive compounds, such as proteins, terpenes, and polysaccharides, which can vary from species to species. For example, lion’s mane mushrooms have been found to improve memory and overall cognitive function by boosting the size of growth cones. Growth cones are essential for the brain cells’ ability to create new connections with other neurons and perceive their surroundings. 

Functional mushrooms are also known to help regulate the immune system by stimulating genes coding expression for proteins associated with immune response. These immune benefits are amplified by the mushrooms’ anti-inflammatory and antioxidant benefits.

what do functional mushroom do for you

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The effects of functional mushrooms are often attributed to alpha and beta-glucans, which are types of polysaccharides. These, along with the high amount of proteins, known as fungal immunomodulatory proteins in functional mushrooms, have been found to offer anti-cancer and immune-boosting properties.  

While the exact way in which functional mushrooms work can be complex, these mushroom varieties don’t produce a “high” or “trip.”

How long does it take for functional mushrooms to work?

It usually takes two to four weeks of consistent use for functional mushrooms to provide noticeable results.

Brief History of Functional Mushrooms

Functional mushrooms date all the way back to 450 BCE, when Hippocrates deemed the amadou mushroom an effective anti-inflammatory with the ability to cauterize wounds. You may have also heard of the Ice Man, Ötzi, who carried amadou and the birch polypore mushroom with him on his quest in the Alps of northern Italy. 

While medicinal mushrooms have been used in many cultures across history, they’re firmly rooted in Ayurveda, a holistic method of healing that began in India over 5,000 years ago. Mushrooms including reishi, cordyceps, chaga, and lion’s mane have long been used by Ayurvedic healers to treat a range of health concerns, including inflammation, low immunity, and digestive discomfort.

Functional Mushrooms Benefits

Functional mushrooms may provide an extensive range of health benefits. While these benefits can differ depending on the mushroom species, they may include improved immune function, digestive health, cognitive health, stress management, sleep quality, energy levels, and skin health. Many mushroom varieties are also known to provide antioxidant and anti-inflammatory benefits, which may help curb the long-term risks of chronic inflammation and oxidative stress. 

With consistent use, functional mushrooms could help lower your risk of neurodegenerative disorders, like dementia and Alzheimer’s disease. However, further research is required to confirm these findings.

Supporting Immune Function

Functional mushrooms thought to support immune function: 

  • Cordyceps boosts the adaptive immune system, which can help strengthen immune responses with certain antigens. However, it also has a natural inhibitory effect on immunity that may help treat autoimmune conditions. 
  • Lion’s mane has been found to boost the intestinal immune system in mice, but research in humans is lacking. Nonetheless, this species’ potent anti-inflammatory and antioxidant effects may provide immune support.  
  • Reishi mushrooms are thought to boost the immune system by impacting white blood cell genes. 
  • Chaga may strengthen the immune system and may even inhibit cancer cell generation with its potent antioxidant properties. 
  • Turkey tail mushrooms are nonspecific immune modulators, meaning that they can boost or suppress the immune system, which may help treat autoimmune disorders, depending on the application. 
  • Shiitake mushrooms have been found to improve immunity with regular use. 
  • Tremella mushrooms exhibit immune-enhancing properties. 
  • Maitake mushrooms have been shown to increase immune defense, particularly in combination with shiitake mushrooms.
  • Oyster mushrooms have been found to strengthen the immune system by activating a molecule that’s essential for infection defense. 
Boosting Digestive Health

Functional mushrooms associated with supporting digestive health:

  • Cordyceps offers potential prebiotic benefits, helping to maintain a healthy gut microbiota. 
  • Lion’s mane supports digestion by preventing the loss of antioxidant enzymes in the stomach, which in turn prevents damage to the stomach’s mucous membrane.
  • Reishi mushrooms may provide prebiotic benefits.
  • Turkey tail can act as a prebiotic to help balance the gut microbiome.  
  • Tremella mushrooms’ benefits for digestion need to be confirmed with human studies. However, in a 2021 study, this species was found to reduce colon swelling and improve intestinal flora in mice. 
  • Maitake mushrooms have a prebiotic effect to help maintain the gut microbiota. 
Improving Cognitive Function

Functional mushrooms thought to improve cognitive function:

  • Lion’s mane is widely considered the best functional mushroom to improve and protect cognitive function. Clinical research has found that with daily consumption, it may significantly improve cognitive function while preventing cognitive decline. 
  • Cordyceps has been found to provide neuroprotective benefits to preserve cognitive function in animal studies. Further research is required to confirm these findings for humans. 
  • Reishi mushrooms also show promise for cognitive function, although further research is needed to confirm this benefit in humans. 
  • Chaga offers antioxidant properties for the brain that may positively affect learning and memory.
  • Turkey tail mushrooms contain compounds with antioxidant properties that may offer neuroprotective benefits.
  • Tremella has been found to improve memory and cognition in people with subjective cognitive impairment.   
  • Maitake contains polysaccharides that may improve cognitive function by preventing oxidative stress. 
Supporting Stress, Anxiety, and Depression Management

Functional mushrooms associated with supporting stress, anxiety, and depression management:

  • Cordyceps has adaptogenic properties that may help the body adapt to certain types of stress, including fatigue, illness, and depressive symptoms.
  • Lion’s mane is an adaptogenic mushroom that’s been found to reduce symptoms of anxiety and depression, however, more research is still needed.
  • Reishi is considered an adaptogenic mushroom that has been shown to reduce depressive symptoms, as well as increase levels of happiness and overall quality of life in some individuals. 
  • Shiitake mushrooms contain nutrients that can lower stress responses and provide natural calming benefits. 
  • Oyster mushrooms, when consumed more than once a month, are associated with a lower risk of depressive symptoms
Regulating Sleep

Functional mushrooms associated with sleep regulation:

  • Cordyceps has been found to increase non-rapid eye movement (NREM) in rodent studies, leading to prolonged sleeping time. In a small study of people with depression, cordyceps didn’t provide an improvement in insomnia at the dose given, but was found to be safe with minimal side effects. More research on its effects on humans is still needed, as it shows promising sleep regulating effects . 
  • Lion’s mane has been found to significantly improve symptoms of sleep disorders in certain individuals.
  • Reishi has been found to improve sleep in people with insomnia.
Supporting Energy and Endurance

Functional mushrooms that may support energy and endurance: 

  • Cordyceps has been found to improve people’s tolerance to high-intensity exercise by increasing energy and oxygen use during physical activity. 
  • Lion’s mane may support sustained energy by promoting stable blood sugar levels, however more research is still needed. 
  • Reishi has been found to reduce symptoms in individuals with chronic fatigue syndrome, contributing to an improvement in overall quality of life.
  • Turkey tail mushrooms have been found to improve exercise performance and reduce fatigue in mice, but further research is required to confirm these findings in humans. 
  • Tremella mushrooms have been found to provide anti-fatigue and anti-anoxia effects. Anoxia describes when the brain or body stops getting oxygen. 
  • Oyster mushrooms have been found to benefit glucose metabolism, which may promote higher energy levels. 
Reducing Inflammation

Functional mushrooms that may help reduce inflammation: 

Boosting Antioxidant Effects

Functional mushrooms that are associated with antioxidant effects: 

Improving Skin Health and Radiance

Functional mushrooms associated with improving skin health:

  • Cordyceps, when applied topically, may reverse or prevent UVB damage to the skin. 
  • Lion’s mane antioxidant effects have been found to boost collagen in rodents, but research on its effects on human skin is limited.
  • Reishi mushrooms have been found to enhance skin quality and effectively treat skin conditions
  • Chaga mushrooms prevent oxidative DNA damage, which may protect skin cells against damage. 
  • Shiitake mushroom extracts are found in popular skincare products (such as Aveeno Positively Ageless) to enhance skin health
  • Tremella polysaccharides naturally hydrate the skin and can help repair the skin barrier. 
  • Maitake mushrooms are thought to reduce skin irritation and improve hydration.
  • Oyster mushrooms may provide anti-inflammatory and antioxidant benefits in skincare applications

List of Best Functional Mushrooms

(*) adaptogenic properties



May help with:

  • Immunity
  • Digestion
  • Cognitive function
  • Stress
  • Sleep
  • Energy 
  • Inflammation
  • Skin health

Optimal daily supplement dose: 1-3g

lion's mane

Lion’s mane*

May help with:

  • Immunity
  • Digestion
  • Cognitive function
  • Anxiety
  • Sleep
  • Energy 
  • Inflammation
  • Skin health

Optimal daily supplement dose: 0.5-3g



May help with:

  • Immunity
  • Digestion
  • Cognitive function
  • Anxiety and depression
  • Sleep
  • Energy 
  • Inflammation
  • Skin health

Optimal daily supplement dose: 6-12g


May help with:

  • Immunity
  • Cognitive function
  • Inflammation
  • Skin health

Optimal daily supplement dose: 0.5-2g

Turkey Tail

Turkey tail*

May help with:

  • Immunity
  • Digestion
  • Cognitive function
  • Exercise performance

Optimal daily supplement dose: 1-3g



May help with:

  • Immunity
  • Stress
  • Inflammation
  • Skin health

Optimal daily supplement dose: 1-3g



May help with:

  • Immunity
  • Digestion
  • Cognitive function
  • Energy 
  • Inflammation
  • Skin health

Optimal daily supplement dose: 1-3g



May help with:

  • Immunity
  • Digestion
  • Cognitive function
  • Inflammation
  • Skin health

Optimal daily supplement dose: 2g



May help with:

  • Immunity
  • Depression
  • Energy
  • Inflammation
  • Skin health

Optimal daily supplement dose: 1-3g

More research still needs to be done on functional mushrooms. Many studies use a small sample size or only involve animals.

Function Mushrooms Side Effects

Functional mushrooms can trigger side effects in some individuals, such as:

  • Dizziness
  • Itchiness
  • Nausea
  • Dry mouth
  • Upset stomach
  • Skin rash

If you experience any side effects, reach out to your healthcare provider right away.

When to Seek Urgent Medical Care

Seek urgent medical care if you experience symptoms of a severe allergic reaction, including swelling of the tongue, lips, or throat, shortness of breath, difficulty breathing, wheezing, fainting, vomiting, and diarrhea.

Who Should Not Take Functional Mushrooms?

Pregnant or breastfeeding individuals shouldn’t take functional mushrooms due to a lack of research into their safety for these groups. Additionally, people with chronic medical conditions should talk to their doctors before taking functional mushrooms.

How to Find the Best Functional Mushrooms to Take

If you decide to take functional mushrooms, it’s essential to find a trustworthy supplier, either online or in your local health food shop. It may be easier to find detailed sourcing information when shopping with an online mushroom supplier.

Before making your purchase, try to find the following details about the supplier:

  • Where the mushrooms are grown
  • Whether the mushrooms were grown with pesticides
  • What materials the mushrooms were grown in, ideally an organic medium like rice or oats 
  • Whether the product contains the mycelium and/or the fruiting body
  • If the product has undergone third-party testing or earned any certifications

In general, look for USA-grown mushrooms that are grown in organic, natural mediums. Ideally, they are non-GMO, organic, and have been third-party tested. 


Functional mushrooms may provide several benefits for individuals looking to naturally enhance their wellness, including improved cognitive function, relief from inflammation, and free radical protection. They’re available in a range of forms to suit different preferences, including infused coffee beans, tea bags, powders, drops, and supplements. 

Functional mushrooms may cause side effects like nausea, upset stomach, and dizziness in some individuals. Individuals who are pregnant, breastfeeding, or being treated for an underlying medical condition should avoid taking functional mushrooms, or only do so as instructed by a physician. 

However, some individuals looking to enhance or maintain their wellbeing with herbal supplements may benefit from the health-boosting properties of functional mushrooms. 


Are functional mushrooms FDA-approved?

Functional mushrooms aren’t FDA-approved to treat any medical conditions.

Can you eat too many functional mushrooms?

Yes, eating too high of a dose of functional mushrooms can cause upset stomach and other side effects. Start with a small dose and gradually increase your dose as needed to achieve the desired results. Be sure to always follow supplement package instructions and discuss the use of supplements with your healthcare provider prior to trying them.

Can you take reishi and lion’s mane together?

Yes, reishi and lion’s mane are often taken together for combined benefits.

How do functional mushrooms make you feel?

Functional mushrooms likely won’t cause an immediate difference in how you feel, but may make you feel more energized, focused, and well-rested over time.