What Are Functional Mushrooms and How Do They Work in the Body?

Mushrooms have been part of human diets and healing traditions for thousands of years. Still, in the last decade, one group has experienced explosive popularity: functional mushrooms, also known as adaptogenic mushrooms.

They’re now found in coffees, capsules, powders, gummies, and wellness blends, available in health shops and online. But what are they exactly? And what do they actually do inside the body?

If you’ve ever wondered whether functional mushrooms could support your focus, stress resilience, sleep, or immune system, but want a grounded, science-informed explanation rather than hype, this guide will walk you through the essentials.

What Are Functional Mushrooms?

Functional mushrooms are fungi that contain naturally occurring compounds believed to support different aspects of well-being, such as immunity, digestion, resilience to stress, or cognitive function. These compounds include beta-glucans, terpenoids, phenolics, and various polysaccharides, many of which are being explored for their roles in inflammation, gut signalling, and antioxidant capacity.¹

Unlike culinary mushrooms, which are mostly valued for flavour and nutrition, functional mushrooms sit somewhere between traditional herbal medicine and modern nutritional science. They’re not replacements for medical treatment, but people use them for general wellness and daily support.

You’ll find them in powders, capsules, tinctures, drink mixes, and extracts. In the UK, for example, they’re sold legally as food supplements and must follow UK supplement and advertising regulations.

Functional Mushrooms vs Adaptogenic Mushrooms

It helps to picture functional mushrooms as the broad, overarching family, an entire toolbox of fungi known for their potential wellness-supporting properties.

Within that toolbox sits a smaller group: adaptogenic mushrooms, which are specifically associated with helping the body respond to physical or emotional stress in a more balanced way. The two categories overlap, but they aren’t identical, and understanding the difference sets more realistic expectations.

Functional mushrooms cover a wide range of species. They’re explored for their potential roles in immune balance, antioxidant activity, cognitive support, and even gut health. Common members of this group include:

• Lion’s mane
• Reishi
• Shiitake
• Maitake
• Chaga
• Turkey tail

The key thing to remember is that functional mushrooms can support different systems in gentle, wide-ranging ways, but being “functional” doesn’t automatically make them adaptogenic.

Adaptogenic mushrooms, on the other hand, are a more specific subset. These are the mushrooms traditionally associated with helping the body maintain homeostasis; essentially, its internal equilibrium, especially when dealing with stress. Examples often cited include:

• Reishi
• Cordyceps
• Chaga
• (Some practitioners also place lion’s mane in this category, though opinions vary.)

Adaptogens typically follow a few general principles:

• They’re considered non-toxic at normal doses
• They may support balanced stress responses
• They’ve historically been used to help restore physical and emotional steadiness

Modern research is exploring these ideas, but much of the current evidence still comes from early-stage, preclinical, or small-scale human studies; therefore, adaptogenic claims should be viewed as promising rather than definitive.³

Taken together, this distinction shows that a mushroom can be beneficial without necessarily being adaptogenic, and that each category offers its own unique role in the wider world of functional fungi.

How Functional Mushrooms Work in the Body

Many people wonder, “How do functional mushrooms work in the body?” The simplest answer is that they interact with pathways involved in immunity, stress regulation, and cellular balance. The idea that a mushroom can support the immune system or help alleviate stress may sound vague, but emerging research is beginning to clarify the underlying mechanisms.

Functional mushrooms contain beta-glucans, a type of polysaccharide that interacts with receptors in the gut and immune system, including Dectin-1 and CR3. These interactions are thought to help modulate, not “boost”, immune responses.² Instead of switching the immune system “on,” beta-glucans appear to help balance signals, allowing the body to respond more appropriately.

Many functional mushrooms also contain antioxidants, including phenolic compounds and, in the case of chaga, melanin-like pigments known for absorbing oxidative stress.³ These antioxidant compounds may help reduce damage from free radicals. Some species act on more specialised pathways:

• Lion’s mane: Contains compounds like hericenones and erinacines, which have been shown in preclinical studies to stimulate nerve growth factor (NGF), a protein linked with neuron health. Human research is growing, but it is still in its early stages of development.⁴⁵
• Reishi: Rich in triterpenes, studied for their effects on stress modulation, sleep quality, and immune cell activity. A recent meta-analysis synthesised available human trials and suggests cautious potential for stress and fatigue support.⁶
• Cordyceps: Contains cordycepin, a bioactive compound linked to mitochondrial support, energy production pathways, and cellular resilience in early studies. Human evidence is developing, but it is widely used as an energy-support supplement.⁸⁹

Each mushroom interacts differently with the body, but they share one theme: they appear to work through subtle, system-wide influences rather than acute, stimulant-like effects.

Potential Benefits of Functional Mushrooms

When people discuss the benefits of functional mushrooms, they’re usually referring to gentle, system-wide effects that build gradually, rather than dramatic or immediate changes. Functional mushrooms often feel subtle because their effects develop over time. While research is still evolving, several areas have consistent early evidence or long historical use.

Brain Function and Focus

Lion’s mane is the most researched mushroom in this area due to its NGF-related compounds. Several small studies and user reports have described improved concentration or mental clarity. Scientists believe this may be linked to neurotrophic pathways, but research is ongoing.⁴⁵

Sleep Support

Reishi has a long tradition in East Asian herbal medicine as a “calming” mushroom. Modern studies suggest its triterpenes may influence stress pathways and relaxation, creating a milder, gentler effect than sleep medications.⁶⁷

Anti-inflammatory Effects

Many functional mushrooms have antioxidant compounds that help regulate inflammation, rather than “block” it. Chronic inflammation is linked to stress, diet, sleep loss, and environmental factors, and mushrooms may play a small, supportive role.¹³

Energy and Endurance

Cordyceps is the star here, often used by athletes or individuals seeking more consistent daytime energy. Cordycepin and related compounds may influence mitochondrial efficiency and ATP pathways, though human studies are still limited.⁸⁹

Popular Types and Their Unique Effects

The most commonly discussed functional mushroom types, lion’s mane, reishi, cordyceps, and chaga, each offer different properties based on their unique bioactive compounds. Below is a quick overview of four of the most widely used functional mushrooms.

Lion’s Mane

Often called the “brain mushroom”, lion's mane is linked with focus, mental clarity, and cognitive wellness. Its preclinical evidence around NGF pathways makes it particularly interesting for people seeking nootropic support.

Reishi

Reishi is associated with relaxation, immune modulation, and sleep support. Many users describe it as a “wind-down” mushroom. Its triterpenes are widely studied for stress-modulating properties.

Cordyceps

Cordyceps is favoured for supporting energy, stamina, and performance, without the jitteriness associated with caffeine. Research suggests its compounds may support mitochondrial function, though results can vary.⁸⁹

Chaga

Chaga is renowned for its antioxidant density. Its dark pigment comes from high melanin levels, which may help absorb oxidative stress. It’s also used traditionally for immune support.

Functional Mushroom Supplements

Choosing a mushroom supplement can be surprisingly confusing. This is especially true because people often search for things like the best functional mushroom powder, even though quality depends more on extraction methods and beta-glucan content than brand name. Powders, capsules, tinctures, and dual extracts—there’s a lot to compare.

Powders vs Capsules vs Extracts

Here’s a simple plain-text table to help:

Extraction matters because some beneficial compounds (like triterpenes) require alcohol extraction, while others dissolve in hot water. High-quality brands often use dual extraction to capture the full spectrum. Look for third-party testing, beta-glucan percentages, and clear species identification.

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Dosage and Safety Considerations

There is no universal dose for functional mushrooms. Different extracts have different concentrations. The best guidance is to follow the product label and consult a professional if unsure.

Possible mild side effects include digestive changes, sensitivity, and, in rare cases, interactions with medications such as anticoagulants or immunomodulating drugs. People with autoimmune disorders should seek medical advice.

Should You Add Functional Mushrooms to Your Daily Routine?

Functional mushrooms offer a gentle, gradual approach to wellness. They don’t behave like stimulants, nootropics, or pharmaceuticals; instead, they tend to influence systems gradually rather than producing immediate, noticeable effects.

If you’re curious, a practical approach is to try one mushroom at a time. For example, lion’s mane for focus, reishi for relaxation, or cordyceps for energy, and observe how you respond over a few weeks.

People who benefit most tend to be consistent, observant, and patient. When exploring functional mushrooms, choose reputable products, check beta-glucan levels, and ensure any supplement aligns with your lifestyle rather than complicating it.

References

1. Dilrukshi N, Grice ID, Mallard B, Tiralongo J. Mushroom β-glucans as immunomodulators: Elucidation of structure-function relationship. Food Chemistry. 2025;495:146468. doi:https://doi.org/10.1016/j.foodchem.2025.146468 ↩︎
2. Han B, Baruah K, Cox E, Vanrompay D, Bossier P. Structure-Functional Activity Relationship of β-Glucans From the Perspective of Immunomodulation: A Mini-Review. Frontiers in Immunology. 2020;11. doi:https://doi.org/10.3389/fimmu.2020.00658 ↩︎
3. Wang Y, Gu J, Wu J, et al. Natural Products and Health Care Functions of Inonotus obliquus. Current Issues in Molecular Biology. 2025;47(4):269-269. doi:https://doi.org/10.3390/cimb47040269 ↩︎
4. Qiu Y, Lin G, Liu W, et al. Bioactive substances in Hericium erinaceus and their biological properties: a review. Food Science and Human Wellness. 2024;13(4):1825-1844. doi:https://doi.org/10.26599/FSHW.2022.9250152 ↩︎
5. Spangenberg ET, Moneypenny A, Bozzo GG, Perreault ML. Unveiling the role of erinacines in the neuroprotective effects of Hericium erinaceus: a systematic review in preclinical models. Frontiers in Pharmacology. 2025;16. doi:https://doi.org/10.3389/fphar.2025.1582081 ↩︎
6. Jafari A, Helia Mardani, Zahra Mirzaei Fashtali, Bahareh Arghavan. The Nutritional Significance of Ganoderma lucidum on Human Health: A GRADE‐Assessed Systematic Review and Meta‐Analysis of Clinical Trials. Food Science & Nutrition. 2025;13(6). doi:https://doi.org/10.1002/fsn3.70423 ↩︎
7. Li K, Liu W, Wu C, et al. The anti-fatigue and sleep-aiding effects vary significantly among different recipes containing Ganoderma lucidum extracts. Heliyon. 2024;10(10):e30907-e30907. doi:https://doi.org/10.1016/j.heliyon.2024.e30907 ↩︎
8. Tian HY, Yu DJ, Xie T, et al. Cordycepin alleviates metabolic dysfunction-associated liver disease by restoring mitochondrial homeostasis and reducing oxidative stress via Parkin-mediated mitophagy. Biochemical Pharmacology. 2025;232:116750. doi:https://doi.org/10.1016/j.bcp.2025.116750 ↩︎
9. Yu H, Hong X, Liu L, et al. Cordycepin Decreases Ischemia/Reperfusion Injury in Diabetic Hearts via Upregulating AMPK/Mfn2-dependent Mitochondrial Fusion. Frontiers in Pharmacology. 2021;12. doi:https://doi.org/10.3389/fphar.2021.754005 ↩︎