Why Does Mushroom Coffee Cause Side Effects?

The Bones Coffee Company Team The Bones Coffee Company Team
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The unique reactions from mushroom coffee stem from a powerful synergy. You’re not just drinking caffeine; you’re consuming a complex mix of bioactive compounds from mushroom extracts like beta-glucans and polysaccharides. These beneficial compounds are celebrated for their health-supporting properties, but can be potent when consumed in excess or on an empty stomach.

Unlike traditional coffee or standalone mushroom supplements, mushroom coffee creates a synergistic effect that your body may respond to differently.

Science in a Sip: A Cheat Sheet

Here’s your quick “brew-down” on what’s really in that cup.

  • Caffeine: Your classic pick-me-up. Brings the buzz, and for some folks, a little bit of jitters related to caffeine intake.
  • Beta-glucans: Help support your immune system, and may get your gut moving.
  • Polysaccharides: Complex carbs your microbiome loves. While it gets acquainted, you might notice a bit of gas or bloating.
  • Adaptogens: Some mushrooms are traditionally described as adaptogenic, meaning they may help your body manage stress.

Key Insight: The side effects aren't from coffee or mushrooms alone, but their powerful synergy. Think of it as caffeine and fungi forming a superhero duo your body’s still learning to trust. 

Side Effects by Mushroom Type

While mushroom coffee is generally safe for most people, each functional mushroom variety has unique properties that may affect individuals differently. Understanding potential side effects can help you adjust your intake and make informed choices about which mushroom blends work best.

Chaga - The Antioxidant King

Known as the "king of medicinal mushrooms," chaga mushrooms are an antioxidant powerhouse. However, they contain oxalates, which can contribute to kidney stones or other kidney problems in very high doses. It also has compounds that affect blood clotting, so consulting with your doctor is vital if you're on anticoagulants or managing blood sugar. 

Reishi Mushrooms - The Chill Shroom

Reishi mushrooms, or Ganoderma lucidum, are the "chill-out" mushroom, celebrated for promoting calm and relaxation. Mushroom coffee containing reishi mushroom powder typically has about half the caffeine of regular coffee, contributing to a smoother, more balanced energy experience. While generally well-tolerated, some sensitive individuals may occasionally experience mild effects like dizziness or dry mouth.

Lion’s Mane - The Brain Booster

This shaggy mushroom is the brainiac of the bunch, linked to enhanced cognitive function. Lion's mane is generally well-tolerated, but because it supports Nerve Growth Factor (NGF), some users may feel a mild tingling sensation. 

Starting with a large dose can also cause digestive problems, similar to those caused by culinary mushrooms in large amounts. Still, many drinkers value it for the benefits of mushroom coffee related to focus and mental clarity.

Turkey Tail - The Gut Guardian

A champ for gut health, turkey tail mushroom is packed with prebiotics that feed good bacteria. This is a huge perk, but the sudden introduction may cause temporary gas and bloating for some people as their gut flora adjusts. This may concern those with IBS or those adding mushroom coffee to their routine for the first time.

Cordyceps - The Energy Engine

The athlete's choice, cordyceps mushrooms, is known for supporting energy. This stimulating effect from Cordyceps militaris can overlap with caffeine’s jolt. If you're sensitive to stimulants, this combo might feel a bit too intense at first, causing anxiety or jitters.

Mushroom Coffee vs. Regular Coffee: How Do the Side Effects Stack Up?

Elegant coffee cups with green floral design

Mushroom coffee offers caffeine, though often about half the amount found in a standard cup made purely from coffee beans. Depending on the mushroom species used and the brewing method, it may provide the same health benefits of focus and energy with fewer jitters.

Potential Side Effect

Mushroom Coffee

Regular Coffee

Jitters & Anxiety

Often lower due to less caffeine and calming adaptogens

Higher risk, especially with multiple cups

GI Impact

Some products may taste smoother or feel gentler on the stomach, though evidence varies by coffee type and individual

Higher acidity can trigger acid reflux, ulcers, or heartburn

Energy Crash Curve

Smoother, more sustained energy without the sharp crash

Prone to the classic afternoon "caffeine crash"

Caffeine (Avg. 8oz Serving)

45–100 mg

95–200 mg

To keep mushroom coffee safe, experts recommend consuming it in moderation and alternating it with regular coffee or decaf to maintain tolerance. Tracking side effects helps you personalize your ideal balance.

Who Should Skip Mushroom Coffee?

Woman in orange sweater holding coffee

While this functional brew is a fantastic adventure for most, some people should pause and consult with a healthcare professional to discuss potential health benefits and risks.

  • Pregnant or breastfeeding individuals: Consider decaf options and consult your physician before trying new products.
  • People on certain medications: If you take blood thinners or diabetes medications, or have kidney concerns, check with your healthcare provider first.
  • Anyone with severe mushroom allergies: This one’s a no-brainer! If you have a known allergy, it's best to steer clear to avoid serious reactions.
  • Those with liver disease: Certain compounds in edible mushrooms could pose health hazards for those with pre-existing liver toxicity concerns.

How to Minimize Mushroom Coffee Side Effects

A young woman in a bathrobe, stretching joyfully while holding a morning coffee

Ready to start sipping safely? Following a few simple rules can make your transition smooth and delicious. Here’s your roadmap to a great experience:

  1. Start with a half-serving. Don't go all-in on day one. Give your body a chance to acclimate.
  2. Sip in the morning. Treat it like regular coffee to avoid any potential interference with your sleep schedule. Enjoying your morning cup helps maximize energy benefits throughout the day.
  3. Hydrate, hydrate, hydrate. Drink an 8-oz glass of water for every cup of coffee you enjoy.
  4. Pair it with food. Having a little something in your stomach can help buffer against any potential digestive upset.
  5. Track how you feel. Note any side effects of mushroom consumption, like headaches or discomfort.
  6. Cycle off one day a week. Giving your body a break can help you stay sensitive to the health benefits of mushroom coffee.

Pro Tip: That first week is your “getting acquainted” phase. Go easy and let your body catch up.

A Quick Look at the Benefits

Better Brain Mushroom Coffee Dark Roast - 10oz

Better Brain Mushroom Coffee Dark Roast - 10oz


The benefits sound impressive, but Harvard Health reminds us that clinical evidence remains limited. While mushroom coffee shows potential for matching or surpassing traditional coffee's benefits, more human studies are needed. Still, countless users appreciate its ability to provide sustained energy without the jitters or afternoon crash, especially when it contains functional mushrooms like reishi and chaga mushrooms.

The benefits of mushroom coffee may range from sharper focus and sustained energy to immune support. Plus, its lower acidity is good for sensitive stomachs. These potential benefits draw many people to explore mushroom extracts in their daily routine.

Bones Coffee’s mushroom coffees are crafted from premium ground coffee beans combined with functional mushroom extracts, so you get a smooth, balanced cup with gentle energy and a clean finish without an earthy aftertaste.

Your Call to Adventure

The golden rule of mushroom coffee is simple: start low, go slow, and listen to your body. By following these pro tips, you're all set to explore this exciting fusion of flavor and function safely and confidently. 

Ready to explore bold flavor without the boring stuff? Bones Coffee Company has 30+ flavorful coffees and single-origin options, all expertly roasted in small batches for maximum freshness. Try a sample pack to find your favorite, or grab our single-serve pods for a quick brew!

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