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How Do You Know If Your Probiotic Is Working? Plus, What To Do If It Isn't

Natalie Butler, RDN, LD
Author: Expert reviewer:
Updated on April 4, 2022
Natalie Butler, RDN, LD
Registered Dietitian Nutritionist
By Natalie Butler, RDN, LD
Registered Dietitian Nutritionist
Natalie Butler, RDN, L.D. is a registered dietitian nutritionist. Since 2007, she has advocated for personalized functional nutrition and nutrigenomics-based lifestyle changes through her private practice Nutrition By Natalie.
Ashley Jordan Ferira, Ph.D., RDN
Expert review by
Ashley Jordan Ferira, Ph.D., RDN
mbg Vice President of Scientific Affairs
Ashley Jordan Ferira, Ph.D., RDN is Vice President of Scientific Affairs at mindbodygreen. She received her bachelor's degree in Biological Basis of Behavior from the University of Pennsylvania and Ph.D. in Foods and Nutrition from the University of Georgia.

Your gut is home to trillions of microorganisms, collectively called the microbiome. They work to aid in digestion, support the immune system, regulate hormones, and generally support gut health.

One of the best ways to support the optimal functioning of your gut is through a well-researched, targeted probiotic supplement, but how do you actually know if it's working?* There are a few telltale signs to look out for—let's dive in.

How your probiotic works

Inside you right now are trillions of microorganisms, some of which are supporting your health by breaking down indigestible fiber, regulating hormones, and communicating across the gut-brain axis.

Other microbial bugs are unfavorable and can negatively impact your health, making you feel sick and sluggish, amongst other things.

How you feel comes down to the overall balance of these microscopic critters.

If there are more good guys than bad guys, then you're probably feelin' good. But sometimes the bad outweighs the good, and gut imbalance occurs.

Consuming probiotics, whether in supplement form or from food, is a good way to work toward a balanced microbiome.* 

Probiotic supplements contain billions of living, beneficial microorganisms.* They typically contain a few different strains of the same microorganisms that already reside in the human body.

When you take a probiotic supplement, you send in backup and add to the population of these naturally occurring microorganisms.

As Robert Rountree, M.D., renowned integrative physician, explains it, "The probiotics are like good cops. We're putting in the good cops, and the good cops can keep watch over the bad guys."*

The new good guys fight against bad bacteria, and promote a healthy gut.* 

The gut is often referred to as the "second brain" because it is interconnected with so many other systems and processes in the body.

By supporting your gut health, you promote not only good digestive health but overall health and well-being.*


The human body contains trillions of microorganisms, some of which can negatively impact your health. A probiotic supplement can help fight against the bad bacteria and promote a healthy gut.*

Signs your probiotic is actually working

That all sounds great in theory, but when it comes down to it, how do you know if your probiotic is actually doing anything?

You can tell if a probiotic is working for you by keeping track of any changes to how you feel before and after (give it several weeks or even months).

Try keeping a journal, so you can see if things are improving. Since probiotics are taken orally and must pass through the digestive tract, digestive-related areas of your health are often the first ones to improve.

Here are a few signs that your probiotic is actually working:*

  1. Less irregularity and more regular bowel movements*
  2. Not going too frequently and BMs with normal consistency*
  3. Less bloating 1and more abdominal comfort*
  4. Improvements in glucose levels2 for those with diabetes*
  5. Healthy cholesterol3 levels*

And take note, just because your health needs aren't improving doesn't necessarily mean probiotics won't work for you. You might need to consume a different strain or increase how much you're taking to see changes.

As for timing, be patient. The more unbalanced your gut flora was at baseline, the longer it will take to achieve balance.*

In most cases, you can expect to see some results within two to three weeks, with additional benefits after six weeks.*

How long should you take a probiotic?

Even if you notice improvements right away, continue taking your probiotic.*

Remember that stress, poor diet, certain medications (e.g., antibiotics), unmanaged illnesses (e.g., SIBO, IBS) can worsen your gut microbiome. Make sure to work with a doctor to ensure these triggers are resolved.

Probiotic supplementation is often useful over the long-term on a daily or regular basis, especially considering probiotics might not permanently colonize the gut.

Not to worry, though, despite not making a forever home of your gut, transient probiotics4 still leave a lasting positive impact.*


Probiotic supplementation is often useful over the long-term on a daily or regular basis. Even if you notice improvements right away, continue taking your probiotic.*

Tips for picking a probiotic that will work

If you're looking for a probiotic supplement, then consider a few things to get your money's worth:

  • Choose a broad-spectrum product that provides multiple, science-backed microbial strains. Gut health expert Vincent Pedre, M.D., explains that the Lactobacillus, Bifidobacterium, and Saccharomyces families have some of the most-well studied species, from which a variety of strains have scientific support.
  • Dose should be determined by the science on each strain. This can range from 1-2 billion CFU to 10+ billion colony-forming units (CFUs) per strain (it depends on the strain and its research).
  • Don't forget to feed your gut microbiome too. Eating fiber-rich prebiotic foods like asparagus and garlic is important for helping maintain a healthy gut. Probiotics eat prebiotics, so by eating prebiotic foods, you are helping your gut bugs survive and thrive. 

Dose, species and strain, and length of consumption can greatly influence how much benefit you receive so choose your probiotic wisely.*   


A good probiotic supplement will have multiple, science-backed microbial strains. Eating fiber-rich prebiotic foods is also important for helping maintain a healthy gut.
Probiotic supplements are safe for infants, children, adults, and the elderly; however, those with compromised immune functions are often advised to avoid probiotics. If you are pregnant, breastfeeding, or taking medications, consult with your doctor before starting a supplement routine. It is always optimal to consult with a health care provider when considering what supplements are right for you.
And do you want to turn your passion for wellbeing into a fulfilling career? Become a Certified Health Coach! Learn more here.
Natalie Butler, RDN, LD author page.
Natalie Butler, RDN, LD
Registered Dietitian Nutritionist

Natalie is a registered dietitian nutritionist with a passion to help others live their best life through food, fitness, safer beauty and a healthy lifestyle. She has expertise with a variety of diets and diseases and believes that there is no one-size-fits-all approach for health. Natalie consults for various organizations, like Apple, Inc.,, Head Health, Inc., and others, providing medical review, recipe and video creation, program development and delivery, seminars, and other services. She has also advocated for personalized functional nutrition and nutrigenomics-based lifestyle changes through her private practice Nutrition By Natalie since 2007. Natalie graduated from Stephen F. Austin State University with a Bachelor of Science in Food, Nutrition and Dietetics, and went on to pursue her graduate dietetic internship to become an RDN through Marywood University in Pennsylvania.

Natalie loves spending time with her husband and three children in the kitchen, garden and in nature. She is a foodie at heart and loves most cuisines, but especially spicy Indian and Thai.