Can You Take Too Many Probiotics? 5 Symptoms to Look Out For

Updated on August 20, 2024

Taking too many probiotics isn’t harmful for most, but it can cause unpleasant symptoms like gas and brain fog. As for the recommended daily intake—it varies from person to person. One’s own unique gut microbiome, lifestyle, and health concerns all play a role in determining the ideal number of CFUs per day.

Probiotics seem to be everywhere in one form or another. There are probiotic foods like yogurt and kimchi, probiotic supplements in capsule form, and as of late—products that have been fortified with probiotics (think: certain bottled waters, cereals, dairy-free milk alternatives, and even chocolate). This plethora of probiotic options begs the question: Can you take too many probiotics?

Keep reading to find out how many probiotics are too much, and how to find the right dosage for your specific health needs.

What Are Probiotics?

“Probiotics are live microorganisms that are a natural part of your gut microbiome, or the community of trillions of bacteria that live in your digestive tract,” says registered dietitian and functional medicine expert, Alana Kessler.

More specifically, they reside in your stomach, small intestine, and large intestine (the colon). However, they can also be found in smaller amounts in your mouth, throat, respiratory tract, reproductive tract, urinary tract, and skin.

These microorganisms assist in the breakdown of food, nutrient absorption, and minimizing harmful bacteria. This goes on to promote whole-body health—impacting your immunity, mental health, oral health, skin health, heart health, and metabolism.

Maintaining a Balanced Gut

Believe it or not, your gut microbiome is the foundation of your health. There are three reasons for this:

  • 70-80% of your immune system is in your gut.
  • Your gut is where your body gets rid of metabolic waste and toxins.
  • 95% of your body’s serotonin (the chemical that carries messages between your brain and your body) lives in your gut, too (2, 3).

So when your gut isn’t healthy, a whole list of health issues arise: brain fog, mood swings, diarrhea, constipation, gas, food intolerances, fatigue/low energy, skin problems (like acne, eczema, and psoriasis), allergies, weakened immunity, chronic bad breath, joint pain and inflammation, and gastrointestinal disorders (like irritable bowel syndrome, inflammatory bowel disease, and celiac disease) (1).

When your gut is healthy, there’s a harmonious balance between the good and bad microorganisms—allowing you to have regular bowel movements, fight off  illnesses, feel relief from gas and bloating, and much more.

But as with most things in life, too much of a good thing can turn into a bad thing. Kessler agrees, “One way you can throw your gut’s microbiome out of whack? By having too many probiotics in your system.”

Can You Take Too Many Probiotics?

What’s considered “too many probiotics” varies from person to person. The makeup of everyone’s gut microbiome is unique, and the exact dosing can be tricky to pinpoint. Especially considering that there’s no general recommendation for probiotics either.

Probiotics are measured in colony-forming units (CFU), which indicate the number of living cells of microbes. Many probiotic formulations have billions of CFUs per serving, some containing 1 to 10 billion CFUs per dose, while others contain up to 50 billion or more. 

"There is no dosage that we know of, or study of efficacy that correlates to exact proper dosage of probiotics for everyone," says gastroenterologist Ashkan Farhadi, M.D. "We know that probiotics and certain species of probiotics are important." But their exacting dosing is a tad more cryptic. Additionally, some populations such as those undergoing certain cancer treatments are not recommended to consume large amounts of probiotics. Which is why it is important to speak with your healthcare provider before implementing a supplement.

Depending on your gut microbiome and health needs, you may need a higher or lower CFU count. The next section should offer some helpful insight as to whether or not you’re taking too many.

5 Signs You May be Taking Too Many Probiotics

If you think you’re taking too many probiotics, here are a few potential symptoms to look out for: 

1. Gas

Gas issues are a common symptom of probiotic overload. Initial probiotic use causes gas build-ups due to your body adjusting to new bacteria populations (4).

Excess microorganisms can engage in a ‘feeding frenzy’ when you eat, which ferments the food in your gut into excess air. This excess air can result in excess gas (5).

The excess gas typically doesn’t last long. Usually, people will report excessive gas for several weeks before it subsides because the body adapts to the probiotics. If the excess gas continues after several weeks, it can be an indication of small intestinal bacterial overgrowth (SIBO) (6).

2. Bloating & Stomach Pain

Bloating is another common side effect of probiotic use. The gas released by the microorganisms in probiotics can cause bloating and stomach pain. These can also lead to feelings of nausea and cramping. If you experience these symptoms long-term, it’s evidence of a possible probiotic overload. 

3. Diarrhea

Like gas and bloating, diarrhea is a common symptom of general probiotic use. Similarly, diarrhea should cease after several weeks as your body adjusts to the probiotics. If the symptoms persist longer, it’s a sign of probiotic overload (4).

Long-term diarrhea indicates microbiome imbalance. Assuming there are no other obvious causes such as a food intolerance or underlying condition, excess probiotics are likely responsible (7). 

4. Headaches

Some probiotic-rich foods contain biogenic amines. Biogenic amines are natural compounds with important roles in the body, such as controlling mood, regulating bodily functions, and responding to stress. These include histamine, tyramine, tryptamine, and phenylethylamine (8, 9). In those who are more sensitive to biogenic amines, these substances may cause symptoms including headaches.

Most of these biogenic amines are found in probiotic-rich foods that have been fermented. For example, wine, cheese, certain fish, and dried meat are probiotic-rich foods that undergo fermentation. A probiotic supplement, on the other hand, is unlikely to provide enough biogenic amines to cause headaches. 

5. Brain Fog

“All that extra gas hanging out in your gut doesn’t just impact your body, it can also affect your mind due to the gut-brain connection”, says Kessler. One study found that having excess gas from a bacterial overgrowth can impact your ability to think clearly by messing with your short-term memory, judgment, and ability to concentrate (5). 

So if you’re noticing more brain fog after giving supplements a go, it might be a sign that you need to cut back or stop taking probiotics.

How to Avoid Taking Too Many Probiotics

To avoid taking too many probiotics, you may want to begin with lower doses to gauge how well your body tolerates them. Sometimes, your gut microbiome just needs time to adapt before it can handle larger probiotic doses comfortably. It can take up to two weeks for your body to adjust to the probiotics before the benefits kick in.

Additionally, it's a good idea to start with only one probiotic supplement at a time. This way, you can identify which probiotic strains agree with you and which ones might be causing any potential discomfort or symptoms, if they arise.

Along with reducing your dosage, you can also:

  • Take your probiotics on an empty stomach: Probiotics can produce gas when combined with certain foods. Taking your probiotics on an empty stomach can help avoid that issue and ensure the maximum survivability of the beneficial bacteria. Take your probiotics at least 30 minutes before you eat. 
  • Drink water: Many of the side effects are a result of your digestive system undergoing the process of detoxification. Staying hydrated will speed up the process and keep you from getting dehydrated if you have diarrhea.

As you start your probiotic supplementation, take note of the following: how your body feels when taking probiotics, how you feel when taking certain strains of probiotics, and how you feel with certain doses. And as always, talk to your doctor or qualified healthcare provider before starting supplementation, and be sure to keep them informed of any changes or adverse effects.

Frequently Asked Questions

There are no known contraindications when taking probiotics alongside medical drugs or supplements.

However, there are a few things you should know when taking probiotics with antibiotics, antifungal medications, and immunosuppressants:

  • Antibiotics: If taking a probiotic alongside antibiotics, it's generally recommended to take the probiotic 1-2 hours away from the antibiotic (unless you’re taking a probiotic supplement that’s specifically formulated for taking with antibiotics). This may also be a consideration when taking a probiotic alongside other natural supplements that have an antimicrobial action.
  • Antifungal Medications: If you’re taking antifungal medication or natural supplements with anti-fungal properties, it's recommended to take probiotics at a separate time of day.
  • Immunosuppressants: If you’re taking immunosuppressant medication or steroid medication like prednisone, you should speak to your doctor before taking probiotics.


Kat Kennedy
Article by

Kat Kennedy

Kat Kennedy is the Fitness and Nutrition Editor at NativePath. With a NASM CPT, NCSF CPT, and NCSF Sports Nutrition Certification, she has a passion for giving people the tools they need to feel healthy, strong, and confident.

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    Medical Disclaimer

    This content is for informational and educational purposes only. It is not intended to provide medical advice or to take the place of such advice or treatment from a personal physician. All readers/viewers of this content are advised to consult their doctors or qualified health professionals regarding specific health questions. Neither Dr. Chad Walding nor the publisher of this content takes responsibility for possible health consequences of any person or persons reading or following the information in this educational content. All viewers of this content, especially those taking prescription or over-the-counter medications, should consult their physicians before beginning any nutrition, supplement, or lifestyle program.

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