How Long Does it Take for Probiotics to Work? - Dr. Michael Ruscio, DC

Does your gut need a reset?

Yes, I'm Ready

Do you want to start feeling better?

Yes, Where Do I Start?

Do you want to start feeling better?

Yes, Where Do I Start?

How Long Does it Take for Probiotics to Work?

Restoring the Gut Microbiota Takes Time, and Just How Long May Depend on the Shape of Your Gut Health

Key Takeaways:

  • For most, it’s best to trial probiotics for at least 3 months, however, there are some conditions where probiotics work much more quickly, or much more slowly.
  • To better reduce symptoms, it’s a good idea to remove any dietary triggers during your probiotic trial with a type of elimination-style diet. 
  • To ensure probiotic success, it’s important to pick a high-quality probiotic. 
  • Using triple therapy probiotics is a great way to ensure you see benefit, but it isn’t always required.

If you’re starting a course of probiotics, it helps to have realistic expectations about how quickly they will start working. You don’t want to give up on your probiotic supplements before they’ve had a chance to improve your well-being. You also don’t want to waste money taking probiotic products that don’t have any health benefits for you.

Based on my observation in the clinic, some patients notice the benefits of probiotics as soon as 1–3 days. For others, it takes as long as 8 weeks to see the effects of probiotic supplementation. However, more recent research suggests trialing a minimum of 3 months on probiotics before you can see significant improvements to your gut microbiome and, in turn, overall health.

So how long does it take for probiotics to work for some common health conditions, exactly how this “good bacteria” works to restore the gut, and how to make the right choice in selecting a quality probiotic.

The Timeline for Probiotic Benefits for Digestive Issues & Beyond

Hundreds of studies show the benefits of probiotics for a wide variety of medical conditions, including digestive problems (like IBS, bloating, and Crohn’s disease) as well as several non-digestive symptoms and conditions. Unfortunately, most studies don’t collect daily symptom data. That means that, for most studies, we know that probiotic supplementation was effective, but we don’t know how quickly it worked.

However, more recent studies can give us insight into expectations you can have for how long of a duration will provide benefit. These recent studies have even changed my understanding of how long a probiotic trial should be. 

For example, we already know that probiotics can help irritable bowel syndrome (IBS). That’s because, for IBS and many other medical conditions, probiotics work by restoring balance in your gut bacteria, and addressing the root cause of symptoms. 

I previously believed anywhere from 1–8 weeks to be sufficient, based on previous data and my clinical experience. But a recent meta-analysis suggests a trial of 2–3 months may be best to see benefit for IBS symptoms. So while I wasn’t far off, it shows that it may be worth sticking it out for longer than we previously thought.

Let’s go over a snapshot of different probiotic timeframes depending on your condition. 

It’s important to note that the timeframe for seeing benefits is the minimum duration, meaning it may take up until that point to see health benefits. It does not mean that’s when you should stop taking probiotics. If you’re seeing benefits, it’s likely worth sticking with probiotics. (But we’ll discuss if, when, and how to cut back on the dosage a little later.):

Acute Diarrhea [1, 2, 3, 4]1–5 days
IBS Symptoms [5, 6, 7]2–3 months
Constipation [8]2 months
Nonalcoholic Fatty Liver Disease [9]3 months
Polycystic Ovarian Syndrome (PCOS) [10]3 months
Bacterial Vaginosis (BV) [11]3 months
Dairy Intolerance (and possibly other food intolerances) [12]2 months – 3 years
Bloating [13]4 – 8 weeks

Probiotic Payoff: Sooner For Diarrhea

Though it may take up to 3 months to see the most probiotic payoff, research shows that probiotics work in as little as 1–5 days for acute diarrhea. [1, 2, 3, 4] This is great news if you come down with a case of traveler’s diarrhea (and serves as a reminder to pack your probiotics in case you start experiencing any off bowel movements on your next trip.)

And, of course, as with any supplements, there are some who experience great results sooner due to what is referred to as the placebo effect. In other words, by expecting and believing that the probiotic will work, they experience beneficial effects. Our thoughts are powerful. 

Probiotic Payoff: Later for Food Intolerance

Preliminary research shows that probiotics can be helpful in reducing dairy intolerance. [12] However, it can take anywhere from 6 months to 3 years. 

This study corresponds with what I have seen in my clinical practice. As patients improve their gut health, bloating, fatigue, mood, and many other symptoms can start to abate fairly quickly. However, food intolerances do often persist much longer. The good news, as I have seen many times, is that as gut health improves, food intolerances often do diminish over time. 

Give Probiotics a Helping Hand By Also Removing Dietary Triggers

In addition to taking probiotics, it can be very helpful to identify and eliminate foods that trigger symptoms. Removing foods that cause inflammation can help abate any existing gut dysbiosis (or imbalance) and allow probiotics to do a better job colonizing the gut.

There are several elimination-style diets on offer, like the low FODMAP diet or Paleo diet, that are designed to help you identify food intolerances and are excellent tools for improving your gut health. And while it’s important to avoid foods that trigger reactions, these diets are meant to be short-term. It’s important to gradually reintroduce foods and broaden your diet as much as possible over time so that you can have as little dietary restriction as possible.

It can take some trial and error, and it isn’t always a linear process. You may test a food item several times and continue to react and then suddenly you find you are able to tolerate it in moderate quantities. Fortunately, based on the research so far, long-term probiotic supplementation is likely to support this process.

For more information about diets that can help eliminate food triggers, see Finding the Right Diet for Your Gut.

Bottom Line: For most conditions, take probiotics for at least 3 months to see if they work for you. Acute diarrhea and food intolerances are exceptions to these guidelines.

How Probiotics Work

Now that we’ve answered the question of “how quickly do probiotics work?”, it’s important to understand why.

Probiotics, to put it simply, are beneficial bacteria that colonize your gut by crowding out bad bacteria. They help balance your gut flora and reduce the burden of pathogenic microorganisms. As the bacteria in your gastrointestinal tract become more balanced, the immune system calms, inflammation reduces, and your digestive health improves.

But it doesn’t stop there. Once your gut is balanced and inflammation reduced, your overall well-being (energy, mood, cognition, immune health, hormonal balance) also improves.

This process explains why it takes time for probiotics to work. It also explains why probiotics have so many different health benefits and few side effects. Research shows the benefits of probiotics for a wide variety of medical conditions, including IBS, Crohn’s disease and colitis, gut infections, mood, sleep, thyroid health, and more. 

For a science-based list of medical conditions that benefit from probiotic supplementation, see my Probiotic Starter Guide.

It’s important to note, however, that while getting any amount of probiotics is a good idea, there’s a pretty large difference between getting probiotics as a dietary supplement or eating probiotic foods. Probiotics are measured in “colony forming units” or CFUs, and fermented foods like kimchi or sauerkraut or drinks like kombucha don’t contain as high of CFUs as supplements. Not to mention you’d have to eat them consistently, every day, to maintain a therapeutic dose.

How to Know If a Probiotic Works For You

Probiotics work well for many medical conditions, but they’re not a panacea that’s guaranteed to work for everyone.

I recommend a trial of 3 months to test their effectiveness for you, even if you’ve tried probiotics before. But it’s important that you do a full and complete trial and follow a few guidelines.

Get It Right in One Go

A lot of people try probiotic supplements without really knowing which probiotic strains to buy or how long to take supplements. They may go on and off probiotic products, trying different brands or different strains of probiotics, hoping for better results. They also may not be informed about selecting a high-quality probiotic supplement.

I call this the probiotics merry-go-round and it can be a waste of time, energy, and money.

Here is some simple advice for implementing an effective probiotic trial. 

Select a High-Quality Probiotic Supplement

The Food and Drug Administration (FDA) doesn’t actually review the quality of probiotics and research shows that some probiotic supplements are not worth buying.

The two most common reasons probiotic products don’t work are:

1) Not meeting label claims 

2) Containing potentially harmful organisms  

Here’s what the research shows:

  • Of 26 commercial probiotics assessed in this study, none fully supported label claims, and some of them contained unacceptable microorganisms [14].
  • One study found only half of the probiotics examined had the specific probiotic strain listed on the label [15].
  • Another study found only 27% of probiotic products had the amount of healthy bacteria listed on their labels [16].

You don’t need to purchase the most expensive probiotic supplements.  But, you should be wary of a probiotic product that is substantially cheaper than the rest.  This usually indicates corners have been cut in the quality assurance measures.  

For specific information on what you should look for in a high-quality probiotic supplement, see my Probiotic Starter Guide.

Select the Right Probiotic Strains

There are a lot of different probiotic strains, but all you really need to know are the three main probiotic categories. Nearly every probiotic product can be classified into one of these categories:

Category 1Lactobacillus & bifidobacterium blendsThese are the most well-researched, with over 500 trials assessing their validity.  These live beneficial bacteria are also known as lactic acid-producing probiotic bacteria.  They typically do not colonize the host, but do improve the health of the host.
Category 2Saccharomyces boulardii (a healthy fungus)The second most researched probiotic, with over 100 studies.  Saccharomyces boulardii (S. boulardii for short) is not a normal part of human microbiota, meaning it does not colonize us but does improve the health and well-being of the host.
Category 3Soil-Based ProbioticsThe third most researched category of probiotics is soil-based probiotics. This group has roughly 14 clinical trials evaluating their effectiveness. This category is also known as spore-forming bacteria. This category of probiotics can colonize the host [17].

This is great news.  This means you don’t need to try every probiotic strain on the market—simply pick one high-quality probiotic product from each category.

You also don’t need to match specific probiotic strains to specific medical conditions. Research shows that all strains of probiotics work in a similar way by addressing the health of your digestive system and can provide benefit. One category of probiotics may be more effective for you than another because of the unique profile of gut flora in your intestinal tract, but you’ll likely see benefit no matter the category you choose.

A great way to ensure you’ll get benefit or that you’re taking the best category for your needs is simple—take them all. This is what I refer to as the “triple therapy” approach, which gives you full exposure to all 3 categories of probiotic bacteria. This approach can be very effective for those who have had poor results with a more haphazard approach to choosing probiotic strains. To do a triple therapy protocol, you can either take a dose from each separate probiotic type, or you can simply take one of my triple therapy powder sticks. I formulated the powder sticks for the exact purpose of making the triple therapy approach easier. 

As we discussed above, it’s a good idea to start by taking all three probiotic strains together for a trial period of at least 3 months.

How to Monitor the Effectiveness of Your Probiotic Supplements

When improvements to your well-being are gradual, they are sometimes easy to overlook. Keeping a written record of symptoms can be very helpful.

Here’s an approach that will help you to be as objective as possible in monitoring the effects of probiotics during your trial:

1st – Take stock of your symptoms 

They might be fatigue and depression, bloating, joint pain, constipation, or insomnia.  Whatever they are, take stock of how frequent and how severe your symptoms are. 

2nd – Reevaluate  

Check in with yourself and ask, “Are my symptoms improving?” If so, keep on the probiotic protocol. Remember, you are not looking for complete resolution, rather a clear trend of improvement. If that’s the case, great, we are on the right track. Keep going.  

3rd – Look for when you hit your peak improvement  

Once you peak or plateau, great. Achieving partial or, ideally, full symptom resolution is arguably the most important milestone when taking probiotics. However, it may feel frustrating if you skip step 1, as it can be challenging to remember where you started. That’s why I encourage my patients to go through this protocol step by step. Keep this constant for another four weeks, so your body can integrate and you can lock in this new level of good health.  

After four weeks…

4th – Find your minimal effective dose  

Technically, you don’t have to do this, but I find less is more with supplements.  I like people to cut their dose of probiotic supplements in half, then reevaluate after 3–4 weeks. If this goes well, try cutting it in half again. If you get to a point where you start to experience symptoms again, then go back to the previous dose you were taking—that’s your “minimal effective dose”.   

There is no one right way of weaning off your probiotic dose. You may want to try a different method. If, at some point, your symptoms return, it means you should stay on the probiotics. You can try weaning again in a few months.  

Probiotics can safely be used in the long term, so if you consistently notice you feel better on them, that is OK.  

If Symptoms Return

You can be going along great, and then something derails your gut health. Things like travel, stress, or a significant period of poor self-care might lead to a regression. It’s OK, life happens. Don’t be hard on yourself. Simply return to the full Probiotic Triple Therapy protocol, and then later, you can again wean your dose. 

What to Do if Probiotics Aren’t Working

If you have been taking a high-quality probiotic supplement and following the Probiotic Triple Therapy protocol for 3 months, and you don’t experience any change in symptoms, you can be confident that you don’t need to try another probiotic product.

With probiotics, you have laid an important foundation that can make other, subsequent, gut therapies more effective.  For example, some people have stubborn imbalances in their intestinal bacteria that may require more than probiotics.  Antibacterial treatments like herbs or even select antibiotics can help here.  Studies have found that probiotics make antibacterial treatments more effective. So we start with probiotics and then consider additional support if needed.   

Probiotic Proof Takes Time

While probiotics can be helpful for a wide range of conditions, there’s also a wide window for seeing probiotic payoff. You can feel symptom relief in a matter of days for conditions like diarrhea, to needing 6 months to really feel the full effects for more stubborn issues. However, a good rule of thumb is to keep up a probiotic protocol for 3 months. 

By also removing foods that cause inflammation you can help probiotics to do a better job colonizing the gut. Elimination-style diets like the Paleo diet or low FODMAP are good short-term diets to use when starting a gut-healing protocol with probiotics. Eventually, you should be able to reintroduce foods and find your minimum effective probiotic dose, so that you can have the most gut-healthy, and least restrictive regimen possible. 

To learn more about different therapies for your gut health be sure to check out my book, Healthy Gut, Healthy You. For personalized help with your healthcare, schedule an appointment at the Ruscio Institute for Functional Health.

The Ruscio Institute has developed a range of high-quality formulations to help our patients and audience. If you’re interested in learning more about these products, please click here. Note that there are many other options available, and we encourage you to research which products may be right for you.

➕ References
  1. Cottrell J, Koenig K, Perfekt R, Hofmann R, Loperamide–Simethicone Acute Diarrhoea Study Team. Comparison of Two Forms of Loperamide-Simeticone and a Probiotic Yeast (Saccharomyces boulardii) in the Treatment of Acute Diarrhoea in Adults: A Randomised Non-Inferiority Clinical Trial. Drugs R D. 2015 Dec;15(4):363–73. DOI: 10.1007/s40268-015-0111-y. PMID: 26541878. PMCID: PMC4662947.
  2. Maity C, Gupta AK. A prospective, interventional, randomized, double-blind, placebo-controlled clinical study to evaluate the efficacy and safety of Bacillus coagulans LBSC in the treatment of acute diarrhea with abdominal discomfort. Eur J Clin Pharmacol. 2019 Jan;75(1):21–31. DOI: 10.1007/s00228-018-2562-x. PMID: 30264164.
  3. Nixon AF, Cunningham SJ, Cohen HW, Crain EF. The effect of Lactobacillus GG on acute diarrheal illness in the pediatric emergency department. Pediatr Emerg Care. 2012 Oct;28(10):1048–51. DOI: 10.1097/PEC.0b013e31826cad9f. PMID: 23023475. PMCID: PMC3760261.
  4. Eskesen D, Jespersen L, Michelsen B, Whorwell PJ, Müller-Lissner S, Morberg CM. Effect of the probiotic strain Bifidobacterium animalis subsp. lactis, BB-12®, on defecation frequency in healthy subjects with low defecation frequency and abdominal discomfort: a randomised, double-blind, placebo-controlled, parallel-group trial. Br J Nutr. 2015 Nov 28;114(10):1638–46. DOI: 10.1017/S0007114515003347. PMID: 26382580. PMCID: PMC4657032.
  5. Yoon H, Park YS, Lee DH, Seo J-G, Shin CM, Kim N. Effect of administering a multi-species probiotic mixture on the changes in fecal microbiota and symptoms of irritable bowel syndrome: a randomized, double-blind, placebo-controlled trial. J Clin Biochem Nutr. 2015 Sep;57(2):129–34. DOI: 10.3164/jcbn.15-14. PMID: 26388670. PMCID: PMC4566021.
  6. Cappello C, Tremolaterra F, Pascariello A, Ciacci C, Iovino P. A randomised clinical trial (RCT) of a symbiotic mixture in patients with irritable bowel syndrome (IBS): effects on symptoms, colonic transit and quality of life. Int J Colorectal Dis. 2013 Mar;28(3):349–58. DOI: 10.1007/s00384-012-1552-1. PMID: 22885882. PMCID: PMC3587687.
  7. Zhang T, Zhang C, Zhang J, Sun F, Duan L. Efficacy of Probiotics for Irritable Bowel Syndrome: A Systematic Review and Network Meta-Analysis. Front Cell Infect Microbiol. 2022 Apr 1;12:859967. DOI: 10.3389/fcimb.2022.859967. PMID: 35433498. PMCID: PMC9010660.
  8. Šola KF, Vladimir-Knežević S, Hrabač P, Mucalo I, Saso L, Verbanac D. The effect of multistrain probiotics on functional constipation in the elderly: a randomized controlled trial. Eur J Clin Nutr. 2022 Dec;76(12):1675–81. DOI: 10.1038/s41430-022-01189-0. PMID: 35927504. PMCID: PMC9708599.
  9. Liu L, Li P, Liu Y, Zhang Y. Efficacy of Probiotics and Synbiotics in Patients with Nonalcoholic Fatty Liver Disease: A Meta-Analysis. Dig Dis Sci. 2019 Dec;64(12):3402–12. DOI: 10.1007/s10620-019-05699-z. PMID: 31203554.
  10. Angoorani P, Ejtahed H-S, Ettehad Marvasti F, Taghavi M, Mohammadpour Ahranjani B, Hasani-Ranjbar S, et al. The effects of probiotics, prebiotics, and synbiotics on polycystic ovarian syndrome: an overview of systematic reviews. Front Med (Lausanne). 2023 Jun 9;10:1141355. DOI: 10.3389/fmed.2023.1141355. PMID: 37359018. PMCID: PMC10288857.
  11. Liu HF, Yi N. A systematic review and meta-analysis on the efficacy of probiotics for bacterial vaginosis. Eur Rev Med Pharmacol Sci. 2022 Jan;26(1):90–8. DOI: 10.26355/eurrev_202201_27752. PMID: 35049024.
  12. Tan-Lim CSC, Esteban-Ipac NAR. Probiotics as treatment for food allergies among pediatric patients: a meta-analysis. World Allergy Organiz J. 2018 Nov 6;11(1):25. DOI: 10.1186/s40413-018-0204-5. PMID: 30425779. PMCID: PMC6218986.
  13. Ringel-Kulka T, Palsson OS, Maier D, Carroll I, Galanko JA, Leyer G, et al. Probiotic bacteria Lactobacillus acidophilus NCFM and Bifidobacterium lactis Bi-07 versus placebo for the symptoms of bloating in patients with functional bowel disorders: a double-blind study. J Clin Gastroenterol. 2011 Jul 1;45(6):518–25. DOI: 10.1097/MCG.0b013e31820ca4d6. PMID: 21436726. PMCID: PMC4372813.
  14. Marinova VY, Rasheva IK, Kizheva YK, Dermenzhieva YD, Hristova PK. Microbiological quality of probiotic dietary supplements. Biotechnology & Biotechnological Equipment. 2019 Jan 1;33(1):834–41. DOI: 10.1080/13102818.2019.1621208.
  15. Ansari JM, Colasacco C, Emmanouil E, Kohlhepp S, Harriott O. Strain-level diversity of commercial probiotic isolates of Bacillus, Lactobacillus, and Saccharomyces species illustrated by molecular identification and phenotypic profiling. PLoS ONE. 2019 Mar 22;14(3):e0213841. DOI: 10.1371/journal.pone.0213841. PMID: 30901338. PMCID: PMC6430388.
  16. Weese JS, Martin H. Assessment of commercial probiotic bacterial contents and label accuracy. Can Vet J. 2011 Jan;52(1):43–6. PMID: 21461205. PMCID: PMC3003573.
  17. Ilinskaya ON, Ulyanova VV, Yarullina DR, Gataullin IG. Secretome of Intestinal Bacilli: A Natural Guard against Pathologies. Front Microbiol. 2017 Sep 1;8:1666. DOI: 10.3389/fmicb.2017.01666. PMID: 28919884. PMCID: PMC5586196.

Need help or would like to learn more?
View Dr. Ruscio’s, DC additional resources

Get Help


I care about answering your questions and sharing my knowledge with you. Leave a comment or connect with me on social media asking any health question you may have and I just might incorporate it into our next listener questions podcast episode just for you!