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Side Effects of Functional Mushrooms (An In-Depth Look)

If you're considering adding functional mushrooms to your wellness routine for their health benefits, you may have some questions about any functional mushrooms side effects you might experience. We've got you covered!

Below, we'll go through potential side effects you might experience when you start taking a variety of functional or medicinal mushrooms. Keep in mind that not every side effect is associated with each and every mushroom supplement or variety. But we've tried to give you some examples of specific mushrooms or mushroom extracts, where applicable, to help you make smarter decisions.

Let's get to it!

What are the Side Effects and Risks of Functional Mushrooms?

While side effects from consuming functional mushrooms or taking mushroom powder are fairly rare, it’s good to be aware of the possibility, however unlikely.

Generally, potential side effects fall into one of three categories — digestive issues, allergic reactions, and interactions with medications or pre-existing health conditions. Let's go over these one at a time.

Digestive Side Effects

"Tummy troubles" from functional mushroom supplements probably have very little to do with the "functional" part of the mushroom you're eating. It could simply be the fiber that's present in every mushroom — functional or not — that's causing the symptoms.

These are typically going to be fairly mild and consist of things like gas, bloating, a low-level stomach ache or — to use a technical term — a general sense of ick. This is much more likely to happen if you eat lots (and lots and lots) of mushrooms.

Bottom line? If you know you generally feel bloated or "gassy" when you eat foods that are high in fiber, functional mushrooms might make you feel the same way.

a wooden bowl with sliced mushrooms and tomatoes

Allergic Reactions

Obviously, if you've had an allergic reaction to mushrooms in the past, you'll want to exercise caution with functional mushrooms as well.

Allergic reactions might range from mild symptoms like itching or hives, to more severe and even life-threatening reactions like anaphylaxis, which can make it difficult or impossible to breathe.

It's always a good idea to start small when trying any new food or supplement, so follow the same advice here if you're unsure whether or not you might be allergic.

Interactions with Drugs or Medical Conditions

Functional mushrooms "do stuff" to your mind, body or both. That's why you take them in the first place. That can cause issues if the effect they have magnifies or lessens the effects of medication you're taking, or if they cause changes in your body that exacerbate an existing medical condition.

For example, some functional mushrooms might have blood-thinning effects (Reishi and Cordyceps are two examples of that). If you're already taking blood thinners for a medical condition, "doubling up" with a big serving of Reishi might pose some risks.

As always, check with your doctor or healthcare provider before you start taking any supplement to ensure it's safe for you.

Are Functional Mushrooms Safe?

There aren't any studies that cast doubt on the safety of functional mushrooms generally. As mentioned above, most people won't have problems taking or eating them, provided you don't overdo it.

That being said, there can definitely be side effects for certain people. We cover these in the section above, but to reiterate, the main problem some people may have with functional mushrooms are mild symptoms of stomach upset and allergic reactions.

Also, for people with certain medical conditions or who are taking some medications, the active compounds in some functional mushrooms could interfere with the medicine or exacerbate your condition. That's why it should be a standard practice to check with your healthcare provider first.

Who Should Avoid Taking Functional Mushrooms?

Man talking with a doctor

For most people, functional mushrooms shouldn't pose a problem. However, there are some groups — generally, people with certain health conditions — that should either avoid adding functional mushrooms or mushroom extracts to their diet or supplement regimen, or at least speak with their doctor first. (Speaking with your doctor is always good advice if you’re considering a new supplement regimen.)

Anyone Pregnant of Breastfeeding

If you're pregnant or breastfeeding (or think you may become pregnant in the near future), it's probably best to hold off on the 'shrooms until you check with your doctor. There's no evidence that shows functional mushrooms might harm an unborn baby or young child, but nor is there any evidence proving conclusively that they don't have an effect on a developing fetus. So again, check with your doctor.

People with Pre-Existing Medical Conditions or Taking Certain Medications

We covered this briefly earlier, but if you have a pre-existing medical condition, or you're taking medication of any kind, always check with your doctor before introducing any supplement, not just functional mushrooms.

For example, if you have high blood pressure and are taking medications prescribed by your doctor to lower it, you could create a dangerous situation if you take Reishi mushrooms. That's because Reishi contains natural compounds that can also lower blood pressure. And the result could create a situation where your blood pressure drops so low that it becomes problematic.

Similarly, if you're taking antiplatelet and/or anticoagulant drugs (drugs that slow blood clotting), taking Lion's Mane can put that into overdrive. Familiarize yourself with the potential effects of any mushroom you plan to take and, of course, ask your doctor first.

Anyone Allergic to Mushrooms

It should go without saying, but let's say it again anyway. If you know you're allergic to mushrooms, functional mushrooms aren't the thing for you. The risks simply don't warrant the rewards in this case.

Can You Take Too Many Functional Mushrooms?

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You've heard the phrase "too much of a good thing?" That applies here too. Take the example above of reishi mushrooms. Something with the ability to lower your blood pressure is probably going to be welcome by a large segment of the population. But, again, lower it too much and you can run into problems. The basic concept is, find a level that provides the potential benefits you're after without veering off into dangerous territory.

There's also the less dramatic effects of overconsumption to consider. If you overdo it, you could be looking at stomach issues ranging from mild to pretty severe. In short, "moderation" should be the watchword of the day.

Is there a Recommended Dosage of Functional Mushrooms?

Yes there is! But we can't tell you what it is. That's because it's going to be different for each and every variety of mushroom. And it might also be slightly different for any one individual depending on how the mushroom interacts with your system, what your goals are, other medical conditions you have, supplements you're taking, or medications you've been prescribed.

If you're taking medicinal mushroom supplements that come "in a bottle" — i.e. a mushroom supplement in powdered form or in a capsule — follow the manufacturer's recommended dose to reduce the chances of side effects. You can always adjust up or down from there.

Benefits and Reasons Why You Might Want to Consume Medicinal Mushrooms

close-up photography of white mushrooms in green grass

As we've covered throughout this article, there are many potential benefits of functional mushrooms — both for your mind and for your body. Here's a brief summary of just some of the reasons so many people are adding medicinal mushroom supplements to their wellness routine.

They're natural sources of essential vitamins. This is the simplest reason of all. Mushrooms are just good for you! They're packed with vitamins, along with important fiber that your body needs anyway.

They can be a powerful source of antioxidants. Many varieties of mushrooms are very powerful antioxidants, compounds that attack free radicals in your body and support your immune system. Some varieties contain more of these compounds than others, but in general you'll find that most mushroom supplements carry at least some antioxidant properties.

They can provide a brain boost. Certain varieties of mushroom supplements are prized for their ability to boost mental performance. Lion's Mane, for example, shows great promise for its ability to reduce brain fog and help boost mental focus and clarity.

They're wonderful adaptogens. An adaptogen is a catch-all term for a substance that helps your brain and body cope with and adapt to stressors in your environment. Some mushroom supplements, like a Reishi mushroom supplement (which includes Reishi mushroom extract), are known for their ability to alleviate anxiety as well.

They may help boost physical performance. In addition to offering specific benefits, some mushrooms can improve your overall energy level and physical stamina. Athletes, and endurance athletes in particular, love Cordyceps for their ability to help your body utilize oxygen more efficiently, which in turn can help your body perform better for longer periods of time.

Bottom Line: Medicinal Mushroom Supplements are Generally Well-Tolerated Additions to Your Wellness Routine

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Functional edible mushrooms, which have been used for centuries in many cultures for their ability to provide both mental and physical benefits, are now gaining traction for the same reasons throughout the world.

Regardless of the several notable exceptions that we covered above, most mushroom supplements are generally well-tolerated and have few side effects. And chances are, because of the wide variety you'll find today, you'll find one or two (or more) that offer the potential health benefits you're looking for.

We’ve covered the potential health benefits of medicinal mushrooms extensively here. But for more, check out our articles on Functional Mushroom Benefits and Best Functional Mushroom Supplements. You can also find several articles on one of our favorite forms of mushroom supplements – mushroom gummies! At Goomz, we believe we make the best functional mushroom gummies on the market. Check them out here.

For more on that, see our stories on What are Mushroom Gummies, Are Mushroom Gummies Safe, Do Mushroom Gummies Work, Vegan Mushroom Gummies and Mushroom Gummies for Focus.

Good luck in your search!

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