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What Are the Side Effects of Mushroom Coffee?”

Side Effects of Mushroom Coffee

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Key Summary

  • May cause digestive issues like bloating or nausea in sensitive individuals
  • Can interfere with medications, especially immunosuppressants or blood pressure drugs
  • High doses of adaptogens may overstimulate or cause fatigue, ironically
  • Some users report headaches, dizziness, or poor sleep
  • Allergic reactions are rare but possible
  • Not ideal for people with autoimmune disorders or mushroom allergies
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Mushroom coffee is trending—but is it safe for everyone? Learn the negative effects of mushroom coffee, what doctors say, and if it’s the right fit for you.
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Introduction: Mushroom Coffee—A Miracle Brew or a Mellow Scam?

Let’s be honest—mushroom coffee sounds weird at first. But with promises of calm energy, enhanced focus, immunity boosts, and even better digestion, it’s no wonder this earthy brew is showing up in mugs everywhere.

Still, not everyone’s sipping it with a smile.

Despite its adaptogenic fanfare, mushroom coffee side effects are real—and if you’ve ever felt off after drinking a cup of Ryze, Mud\Wtr, or Everyday Dose, you’re not alone. Just check Reddit threads or Amazon reviews: some users report nausea, dizziness, digestive upset, or even anxiety spikes.

So, what gives?

In this article, we’ll explore the negative effects of mushroom coffee, dig into expert opinions, and help you figure out if this buzzy brew is worth the hype—or best left on the shelf.

What Is Mushroom Coffee, Anyway?

Mushroom coffee is typically a blend of regular coffee and medicinal mushrooms, such as:

  • Lion’s Mane – known for cognitive support
  • Reishi – linked to stress reduction
  • Chaga – immune support
  • Cordyceps – energy and endurance booster


These fungi are often dried, extracted, and added to coffee grounds or powders. The result? A functional beverage that promises to provide caffeine without the crash.

But not all bodies react the same—and that’s where things can get tricky.

Common Mushroom Coffee Side Effects (Real Reviews & Expert Input)

1. Digestive Issues

Many users report bloating, stomach cramps, or nausea after trying mushroom coffee for the first time. These side effects are likely due to bioactive polysaccharides and phenolic compounds found in functional mushrooms like reishi and chaga, which can irritate the gastrointestinal tract in sensitive individuals.

According to a 2020 study published in Frontiers in Pharmacology, while reishi and chaga have documented health benefits, they may also trigger adverse effects such as diarrhea, dry mouth, dizziness, or gastrointestinal discomfort, particularly in people new to mushroom supplementation (Guggenheim, 2014)1.

“I felt like I was going to throw up for an hour after drinking Ryze for the first time. Had to stop,” — Reddit user on r/Supplements

2. Overstimulation or Anxiety

Although some blends claim to reduce anxiety, adaptogens can backfire if used improperly or in high doses. Lion’s Mane, for instance, can overstimulate the nervous system in some people, ironically causing insomnia, irritability, or restlessness.

According to a 2020 review in the Journal of Dietary Supplements, individuals with pre-existing anxiety may react unpredictably to neurostimulatory mushrooms like Lion’s Mane (Docherty, 2023)2.

Explore More

3. Medication Interactions

If you’re on blood thinners, blood pressure meds, or immunosuppressants, mushroom coffee could be risky.

  1. Reishi has natural blood-thinning properties
  2. Chaga may affect blood sugar levels
  3. Cordyceps may interfere with steroid-based treatments


Always check with a healthcare provider—especially if you’re undergoing cancer treatment, managing diabetes, or taking autoimmune medications.

4. Fatigue or “Flat” Feeling

Ironically, some users report feeling tired or foggy after mushroom coffee. This may be due to the lower caffeine content combined with adaptogens that lower cortisol.

“I switched to Mud\Wtr for energy and focus but felt more drained after a week. Coffee worked better for me.” — Amazon reviewer

5. Allergic Reactions

While adaptogenic mushrooms like reishi and cordyceps have promising benefits, they may also produce side effects in sensitive individuals. According to a 2019 review published in the International Journal of Molecular Sciences, compounds in functional mushrooms can lead to mild digestive issues, skin rashes, or central nervous system effects such as insomnia or dizziness when taken in high doses or without proper standardization (Gao, 2003)3.

Ryze vs. Everyday Dose Mushroom Coffee: Which Is Better?
Drinks The Tweak Lab

Ryze vs. Everyday Dose Mushroom Coffee: Which Is Better?

Trying to decide between Ryze and Everyday Dose mushroom coffee? This expert comparison covers taste, ingredients, effects, and cost—helping you choose the best brew for focus and sustained energy.

What Experts and Doctors Say About Mushroom Coffee

While functional mushrooms like Reishi, Lion’s Mane, and Cordyceps have shown promise for immune support, energy, and cognitive enhancement, they are not free from side effects. Experts emphasize that the effects depend on the individual, dosage, and formulation.

According to the Integrative Medicine Research journal, Reishi mushroom can cause side effects such as dry mouth, throat irritation, upset stomach, nosebleeds, and skin rashes, especially when taken in high doses or over extended periods (Li et al, 2024)4.

Further, a double-blind, placebo-controlled study published in the International Journal of Medicinal Mushrooms found that some participants experienced mild gastrointestinal symptoms, such as nausea and dry mouth, after taking Ganoderma lucidum (Reishi) extract daily (Gao, 2003)3.

These findings highlight the importance of starting with a low dose, monitoring your body’s response, and speaking to a healthcare provider—especially if you’re on prescription medication or managing chronic health conditions.

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Who Should Avoid Mushroom Coffee?

You might want to skip mushroom coffee if you:

  • Have a mushroom allergy
  • Take immunosuppressive drugs or blood thinners
  • Are pregnant or breastfeeding (safety data is lacking)
  • Have autoimmune conditions (consult your doctor)
  • Suffer from anxiety or sleep issues

Common Side Effects of Mushroom Coffee

Top 5 Mushroom Coffee Side Effects + % of Users Reporting (based on reviews)

Side Effect

% of Users (Approximate)

Digestive discomfort

30%

Fatigue / Drowsiness

20%

Insomnia or jitteriness

15%

Headaches

10%

Allergic reaction

<5%

FAQs

Doctors acknowledge that mushroom coffee may offer cognitive and immune benefits, but they also warn about its lack of regulation, possible medication interactions, and digestive side effects. It’s generally safe for healthy adults but not suitable for everyone, especially those with autoimmune diseases or allergies.

People with mushroom allergies, autoimmune disorders, or those on immunosuppressants or blood thinners should avoid Ryze. Also, those sensitive to adaptogens or low caffeine may experience fatigue or stomach discomfort.

Daily mushroom coffee may support focus, energy, and stress reduction, but it can also cause digestive issues, interactions with meds, or adaptogen overload. Most users tolerate it well, but long-term effects depend on individual health status and dosage.

How to Reduce Mushroom Coffee Side Effects: Pro Tips From Experts & Users

Tried mushroom coffee and felt bloated, dizzy, or foggy? You’re not alone—but the good news is, many of the common side effects can be avoided with a few smart tweaks to your routine.

Here’s how to enjoy the benefits without the backlash:

1. Start with a Low Dose

Most side effects come from taking too much too soon—especially if you’re new to medicinal mushrooms like Reishi or Lion’s Mane.

Pro Tip: Begin with half the recommended dose for the first 3–5 days. This gives your body time to adjust to the active compounds (like beta-glucans and triterpenes) that influence immune and neurological function.

2. Time Your Intake Wisely

Some mushroom coffee blends contain Lion’s Mane or Cordyceps, which can be mildly stimulating. Others like Reishi are better suited for the evening because of their sedative properties.

Pro Tip:
Take energizing blends in the morning, and avoid reishi-rich formulas before bed unless they’re marketed as calming or sleep-enhancing. Pay attention to how your body responds over time.

3. Avoid Drinking on an Empty Stomach

Many users report nausea or stomach cramps when they drink mushroom coffee first thing in the morning.

According to a clinical review in the Journal of Agricultural and Food Chemistry, bioactive polysaccharides from fungi can irritate the stomach lining in sensitive individuals—especially when consumed alone (Liu et al, 2025)5.

Try This: Pair your mushroom coffee with a light meal, or take it after breakfast to buffer any gastric irritation.

4. Check for Fillers or Allergens

Not all mushroom coffees are created equal. Some contain:

  • Grain-based mycelium (which can cause bloating)
  • MCT oil, which some people don’t tolerate well
  • Natural flavors or stevia, which may cause GI issues in sensitive folks


Read the label carefully. Look for brands that disclose exact mushroom species, extraction method, and contain 100% fruiting body extract with beta-glucan levels listed.

5. Cycle Your Use (Take Breaks)

Daily use of adaptogens like Reishi or Cordyceps can lead to a build-up or even diminished effect over time. Long-term, constant use may also increase the risk of overstimulation or immune dysregulation, especially in people with autoimmune issues.

Consider using mushroom coffee 5 days on, 2 days off, or take a 1-week break every month to reset your system.

6. Consult a Healthcare Professional

Especially if you’re:

  • Taking prescription meds (e.g., blood thinners, immunosuppressants)
  • Pregnant or breastfeeding
  • Managing chronic conditions like autoimmune disease, IBS, or anxiety


Mushroom compounds like triterpenoids and polysaccharides can interfere with medications or worsen certain symptoms if not properly dosed or combined.

Pro Tip: Bring the ingredient list or product packaging of your mushroom coffee to your naturopathic doctor, registered dietitian, or integrative physician—especially if you’re managing medications or chronic health conditions. They can help determine if it’s a good fit for your body and lifestyle.

Bonus Resource: How to Pick a Safer Mushroom Coffee Brand

Here’s what to look for to reduce side effects from the start:

Label Element

What to Look For

Source

“100% Fruiting Body Extract”

Extraction Method

Dual Extract (water + alcohol) preferred

Beta-Glucan Content

Listed as % or mg/serving

Caffeine Content

Clear dose per serving (match to your needs)

Additives

Avoid gums, “natural flavors”, unnecessary oils

Final Thoughts: Is Mushroom Coffee Worth the Risk?

Mushroom coffee can be a powerful ally—or a not-so-fun experiment gone wrong. If you’re curious, start slow, monitor how you feel, and always check the label (some brands use more filler than function). Better yet, consult your doc if you’re on meds or managing chronic health conditions.

Still curious which blend is best? Check out our deep dive on “Ryze vs. Everyday Dose Mushroom Coffee” to see which one actually delivers.

Disclaimer: This content is for informational purposes only and should not be considered medical advice. Always consult a qualified healthcare provider before making dietary changes.

About the Author

Jalaine McCaskill, founder of Tweaksly, offers practical, research-based nutrition tips and reviews to make healthy eating simple and achievable. Dedicated to distilling complex clinical studies into actionable daily tweaks.

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References:

  1. Łysakowska, P., Sobota, A., & Wirkijowska, A. (2023). Medicinal Mushrooms: Their Bioactive Components, Nutritional Value and Application in Functional Food Production-A Review. Molecules (Basel, Switzerland), 28(14), 5393. https://doi.org/10.3390/molecules28145393

  2. Bak, W. C., Park, J. H., Park, Y. A., & Ka, K. H. (2014). Determination of Glucan Contents in the Fruiting Bodies and Mycelia of Lentinula edodes Cultivars. Mycobiology, 42(3), 301–304. https://doi.org/10.5941/MYCO.2014.42.3.301

  3. Burdick, C. (2025, October 22). Fruiting Body or Mycelium? Navigating the Mushroom Extract Debate. Retrieved from Select Ingredients: https://selectingredients.com/blog/fruiting-body-or-mycelium#:~:text=Cons:%20The%20obvious%20downside%20is,proper%20mushroom%20extract%20would%20provide.

  4. Wasser S. P. (2014). Medicinal mushroom science: Current perspectives, advances, evidences, and challenges. Biomedical journal, 37(6), 345–356. https://doi.org/10.4103/2319-4170.138318

  5. Rop, O., & Jurikova, T. (2009, November 1). Beta-Glucans in Higher Fungi and Their Health Effects. Nutrition Reviews, 67(11), 624-631. doi:https://doi.org/10.1111/j.1753-4887.2009.00230.x