How Long Does It Take for Probiotics to Work? The Answer May Surprise You

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    A common question when starting probiotic supplements is: “How long does it take for probiotics to work?” Find out what to expect from taking probiotics.

    A common question when considering probiotic supplements is: “How long does it take for probiotics to work?” Understanding the nature of probiotics and digging into the research on their potential benefits can help us better answer this question.

    What are probiotics?

    Everybody loves fermentation! Even if you don’t actually know what it is. Bacteria and yeasts are live microbes that break down, or ferment, foods. This process occurs in your intestines to help make certain nutrients and fuel for your gut cells.

    In food production, fermentation produces gasses and certain flavors that change the taste and textures of foods and beverages. The fermentation process is used to make yogurt, sauerkraut, kimchi, kombucha, and beer.

    Some fermented foods are sources of beneficial microbes called probiotics. For example, certain yogurts have live strains of “good bacteria” added to the milk. These can include strains of Lactobacillus or Bifidobacteria (more on probiotic strains later). Food manufacturers may also add probiotics to foods like smoothies, nutrition bars, and baby formulas.

    While food sources of probiotics may be helpful, it can depend on the types and amounts provided by the food. This is where probiotic supplements come in.

    Probiotic supplements contain live microbes such as bacteria and yeast that can be ingested. Probiotics are currently being researched for a variety of benefits including gut and immune health.

    Most probiotic supplements list the number of colony forming units (CFUs) per serving, so you know how much you are getting. Understanding CFUs will be helpful when discussing the potential benefits of taking probiotics.

    Along with the amount of CFUs, probiotic supplements may also include the strains on the supplement facts label.

    Types or strains of probiotics

    The naming of probiotics is a little nerdy, but this can be really helpful for understanding probiotics. Probiotics are named by their genus, species, and strain. The seven most commonly used genera (plural of genus) of probiotics are:

    • Lactobacillus
    • Bifidobacterium
    • Saccharomyces
    • Streptococcus
    • Enterococcus
    • Escherichia
    • Bacillus

    The full name of a specific probiotic includes the genus first, then the species, then the subspecies (if applicable), and the strain at the end. Here are two examples:

    • Lactobacillus rhamnosus GG
    • Bifidobacterium animalis lactis DN-173 010

    Lactobacillus rhamnosus GG does not have a subspecies, but Bifidobacterium animalis lactis DN-173 010 has lactis as the subspecies.

    We encourage you to take a look at the supplement facts panel the next time you are looking at probiotics. This will help you familiarize yourself with the common strains available and will provide a better understanding of probiotic research.

    A big part of this research is the role that probiotic supplements may play in the health of the gut microbiome.

    What is the gut microbiome?

    Don’t fear the microbes! While terms like microbes and microbiome may sound a little scary, not all microbes are bad. In fact, we have trillions of microbial cells inside of our gut. This complex community of microorganisms including intestinal bacteria, fungi (including yeasts), viruses, and protozoa make up what is called the “gut microbiome” (or microbiota) in all of us.

    The gut microbiome is a hot topic in research, with scientists finding correlations between the balance of microbes in the intestines and gut and immune health. There is also emerging research into the impact of probiotics on brain and metabolic health.

    While the difference between a “balanced” and an “imbalanced” gut microbiome isn’t fully understood yet, it’s clear that most of the microbes in the gut should be beneficial.

    Problems can arise in the microbiome when the balance between good and bad microbes is thrown off. So while everyone’s composition of microbes is unique, there are emerging trends showing what a healthy microbiome should look like. There are also different ways that the balance of microbes can be changed.

    How do probiotics work on the gut microbiome?

    If the gut microbiome does become imbalanced, probiotic supplements may help bring things back into order. Imbalances of microbes can be due to things like antibiotics, food poisoning, or other situations of stress.

    Some critics of the benefits of probiotics state that if probiotics from supplements don’t colonize the gut (or take up long-term residence), then they are not useful. However, others point to studies that have found benefits from probiotics even without colonization.

    Taking probiotics may provide a supportive environment that encourages the growth of the good microbes that are already present in the gut.

    Once the gut microbiome is in balance, foods high in prebiotic fibers can help feed the good microbes and support the long-term health of the gut. Prebiotic-rich foods include asparagus, bananas, oats, and onions and garlic. Prebiotics can also be found in supplements as capsules or powder.

    Benefits of taking a probiotic

    As we have already discussed, the research on the benefits of taking probiotics continues to grow and extends to almost every area of health. Probiotics have been studied for everything from gut and skin health, to immune support and brain health.

    Healthy Adults

    We will get into the research on probiotics for supporting certain body systems, but let’s first talk about using probiotics in healthy adults. One review article found that probiotic supplements led to improvements in the gut microbiota, but only while taking the supplements. The review also concluded that there was not enough evidence to show if probiotics could support healthy blood lipids levels.

    However, since this review included multiple studies, we can not say for sure whether certain strains had a bigger (or smaller) impact than others.

    Gut Health

    A large portion of research on probiotic supplements is focused on gut health support.

    Probiotics have been found to be beneficial when used with antibiotics. The idea is that they can help keep the gut in balance or can bring the gut back into balance when needed.

    Here are some other lifestyle changes that may help your gut if you need to take antibiotics!

    A meta analysis found that probiotics may help with digestive concerns when traveling. As this tends to be a time when different foods may be consumed or sleep patterns may change. Both of these are factors that can impact gut health.

    Research has also shown a potential role for probiotics in occasional constipation and lactose intolerance. Remember those Lactobacillus we talked about? They may actually help break down lactose to make it easier for people with lactose intolerance to tolerate. Although the results from the study demonstrate various strains and different degrees of efficacy, there is an overall positive correlation between probiotics and ability to break down lactose. More research needs to be done. Lactase is a digestive enzyme that has been extensively researched and can serve as a tool to help break down lactose more efficiently. This enzyme can be found in our digestive enzyme supplement.

    Finally, a review on the research looking at probiotics found them to be beneficial . One interesting note that the authors made is that single and multi-strain probiotics seemed to have similar benefits.

    Immune Health

    Research continues to show that the gut microbiome plays a major role in the health of our immune system. A healthy microbiome supports the immune system, and a healthy immune system supports the microbiome.

    Research into the mechanisms of probiotics and the immune system suggests that probiotics may influence the body’s immune response. Other studies have found similar benefits on probiotics for supporting the health of the immune and respiratory system.

    Potential risks and side effects from probiotics

    As you can see, probiotic supplements have been heavily studied on people for a variety of uses. They are generally considered to be safe when used by healthy people.

    Some people may experience digestive side effects like an increase in gas or bloating, especially when first starting probiotics.

    It’s important to talk to your healthcare professional before starting probiotics to discuss the potential risks and benefits.

    When do probiotics start working?

    If you are taking probiotics and have no side effects, that’s wonderful! But you may be wondering how long it takes for probiotics to work.

    If you are taking probiotics to support your gut health, you may notice the benefits within a few days. However, the research on probiotics varies in the length, so this can depend on several factors. Much of the research trials are 1-8 weeks long.

    How to know when your probiotics start working

    In order to know when your probiotics start working, you or your healthcare professional should monitor your response to them. If you are taking probiotics for gut health, consider your bowel movements and digestion.

    Other benefits, like immune health, may be harder to tell the difference. If you are taking probiotics for skin health support, changes may take longer to be noticeable.

    How to monitor your probiotic's effectiveness

    A good way to monitor your probiotic’s effectiveness is to keep a journal once you start the probiotic. Try not to change anything else in your nutrition and lifestyle routine so you can tell the difference.

    If eight weeks go by and nothing has changed, then you may want to consider why.

    Why a probiotic might not work for you or take longer to work

    Remember those probiotic strains that we talked about? If probiotics are not working for you, it could be because it’s not the right strain or combination of strains. According to a published review on the topic, “the beneficial effects of each probiotic strain cannot be generalized.” Therefore, it’s likely a good idea to take probiotic strains that have been studied for the intended purpose.

    Another reason for probiotics not working is that they may not be potent enough, meaning that they do not contain a high enough CFU to make a difference. You also need to store probiotics as directed (some need to be refrigerated!) to make sure they keep their potency.

    When it comes to dietary supplements, quality is extremely important. Make sure to choose a probiotic supplement that values testing throughout the manufacturing process and that has been third-party tested to ensure you are actually getting what you pay for.

    What to do if your probiotics aren't working for you

    If you have been taking probiotics for a while and do not find them to be helpful, you should first make sure you are taking the supplement as directed. You should also check the storage instructions and expiration date.

    If all checks out, then you should consider the type and brand of probiotic you are taking. It’s possible that a different strain or combination of strains would be better for you. If the supplement is not from a reputable brand that is dedicated to testing their products, consider switching to a brand that is obsessed with quality (like us!).

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    Dr. Carla Montrond Correia ND, CNS
    Medical Content Manager
    Dr. Montrond-Correia is a licensed naturopathic physician and a certified nutrition specialist (CNS). She holds degrees from University of Bridgeport, Georgetown University, and University of Saint Joseph, and supplemented her education with internships in the health and wellness space. She's focused on research, herbal medicine, nutrigenomics, and integrative and functional medicine. She makes time for exercise, artistic activities, and enjoying delicious food.
    Katelyn Wilson, RD
    Freelance Contributor
    Katelyn Wilson is an integrative and functional registered dietitian who is passionate about root-cause approaches to gut health and IBS (irritable bowel syndrome). In addition to running a virtual private practice, Katelyn also writes and consults for healthcare professionals and brands to help promote research-based nutrition and health information.