A healthy gut is one of the key ways we can boost our whole-body health and avoid illness. Gastrointestinal issues like diarrhea and constipation are common responses to different bacteria and viruses invading the gut. Similarly, vaginal infections such as a yeast or bacterial vaginosis occur from an overgrowth of harmful bacteria. All are common but avoidable conditions with the right probiotic therapy.

Probiotics can help keep an optimal level of beneficial bacteria in our digestive system to prevent and treat gastro, vaginal, and other types of uncomfortable infections. But not all probiotics are created equal; nor are they effective at equal rates. Several factors influence how long probiotics take to work. Condition, dose, strain, storage, and even lifestyle can affect their ability to make it to your gut alive and able to colonize.

In this article, we’ll cover how long probiotics take to work in general, and for treating specific, common conditions. You’ll discover why probiotics are your body’s number one supplement for optimizing overall health, and how to select a probiotic to ensure its viability in your large intestine.

Gut Health 101

Probiotic therapy for a gastrointestinal issue can take effect in as little as a few hours. Different conditions may take longer, sometimes up to two months. However, several factors influence their effectiveness and how rapidly they work. Read this guide to find out how long it takes probiotics to work for different conditions.

Your Gut Has a Mind of Its Own


Did you know there’s an entire nervous system inside your gut? It’s called your enteric nervous system, from the Latin word entero, meaning intestine. This intelligent system has more nerve endings than the entire spinal cord, and its ability to function optimally is directly affected by the health of your gut.

As part of the peripheral nervous system, the enteric system has bidirectional communication with the brain via the central nervous system. Scientists call this connection the gut-brain axis. The gut-brain axis impacts your immune system and the efficiency of your intestinal ecosystem, or the microbiome.

The human microbiome can be defined as “the genome of our all our microbes” (1). It has an estimated 100 trillion microorganisms, including bacteria, viruses, and fungi, the bulk of which live in our gut (1). That’s about seven times the number of cells we have in our entire body, which means, biologically speaking, we’re more microbe than human. In a sense, it also means that our guts are more intelligent than our brains. Indeed, scientists believe the microbiome is far more complex and sophisticated than even the human genome.

In an age of mysophobia or fear of germs, we’re doing terrible things to the balance of the microbiome. We must understand why bacteria are a critical part of our health and how probiotic intervention can help maintain an optimal balance.

In their extensive article titled, What is the microbiome, Amon & Sanderson write,

“The human microbiome has extensive functions such as development of immunity, defence against pathogens, host nutrition including production of short-chain fatty acids important in host energy metabolism, synthesis of vitamins and fat storage as well as an influence on human behaviour, making it an essential organ of the body without which we would not function correctly” (1).

Eighty percent (80%) of your immune system is dictated by your digestive system, primarily by the health of your microbiome. Every body system works together to produce either symbiosis or dysbiosis. A healthy gut is, essentially, the foundation of our life force energy.

Gut health also affects cognition, mood, and a variety of physiological processes. That sudden mood swing? Afternoon brain fog? Poor performance at the gym? They could all be the result of insufficient beneficial bacteria in the gut.

What does gut health have to do with how long it takes for probiotics to work?

Probiotics can contribute to better overall health if––and that’s a massive IF––they can survive the cavalry of internal and external forces working against them. The rate at which good bacteria proliferate in your gut is dependent on a variety of factors happening simultaneously to ensure they make it to your large intestine still alive.

If you’re new to probiotic therapy and wondering how they work and how long before you can expect to see benefits, this guide is for you. Perhaps you already know what probiotics are, but you’re wondering how long they take to treat specific conditions. We’ve got you covered there too.

Let’s start with a little background on how lifestyle destroys (or helps) our guts. Then we’ll look at how long it takes for probiotics to work to heal common conditions like bacterial vaginosis, yeast infections, constipation, and diarrhea, among other consequences of impaired gut flora.

What Disrupts Healthy Gut Bacteria?

Our gastrointestinal (GI) tract hosts a massive number of immune cells, along with an estimated 40-100 trillion bacteria cells from more than 500 different species (2).

Many things can contribute to low numbers of beneficial bacteria in the gut that would, in a balanced state, ward off the harmful bacteria. Antibiotics, for example, kill off everything, even the helpful bacteria, and along with a poor diet, they’re one of the primary culprits of gut dysbiosis, even worse in conjunction. According to integrative health expert Ronnie Landis, a startling 95% of antibiotics are not essential.

Our guts are now cultivating antibiotic-resistant bacteria strains in response to the overuse of antibiotics. That’s because they’re continually striving to maintain a state of homeostasis. It’s our body’s intelligent response to our lifestyle.

By wiping out the bad guys, antibiotics are effectively destroying all bacteria––the good ones too. Perhaps it’s time to reconsider our definition of intelligence!

Stress too has a major impact on the condition of our gut flora. Owing to a negative feedback loop involving the endocrine system, how you manage stress can either help or hinder the gut ecosystem. As Scott Anderson explains in The Psychobiotic Revolution, it’s the case with all living systems (3).

What Are Probiotics & How Do They Work?


Probiotics are nonpathogenic microorganisms that, when ingested in the right amounts, positively influence the digestive ecosystem and, consequently, overall health. Probiotics have colony-forming units (CFUs), indicating the number of live strains in each dose and their potential for proliferation in the gut. While we can ingest probiotics in the form of a supplement, they’re alive in well in many of the foods we eat, particularly yogurt, kefir, and sauerkraut. 

There are loads of evidence supporting the benefits of probiotics for improving and preventing various health conditions. That may be because they play an important role in maintaining immunologic equilibrium in the GI tract by directly interacting with immune cells (4).

Probiotics support the body’s immune response, stool consistency, elimination regularity, and vaginal lactobacilli concentration (5). Bifidobacterium longum or bifidobacterium infantis, two common strains now considered technically the same, inhibit pathogens in the large intestine, which can prevent diarrhea and reduce inflammation. Although observable benefits may not appear right away, probiotics may also help improve food allergies and lactose intolerance.

Probiotics and prebiotics (the probiotics’ food) can also improve Type 2 diabetes and cardiovascular disease by improving the microbiome, leading to cholesterol-lowering effects (6). They may also help reduce anxiety and excessive cortisol levels, leading to improved neurological health and better moods.

With benefits like this, why wouldn’t you take probiotics?

Fast Probiotic Intervention: How Long Will It Take for Probiotics to Work?


Rome wasn’t built in a day, and microbiotic colonies aren’t either. In some cases, especially gastrointestinal infections, you may notice a difference within several hours. In other cases, you may not realize until the following spring that your allergies don’t seem to be as bad, that your skin has cleared up, or the weight you’ve tried for years to lose evaporated without strenuous effort. It’s important to note that food, stress, medication, and other factors, may not support your gut’s ability to produce an abundance of beneficial bacteria. Therefore, a probiotic may be more or less effective depending on your lifestyle.

According to authors in Paris, probiotics may modulate immune function and reduce inflammation immediately after reaching the large intestine, which would explain why some people notice probiotics working quickly with certain conditions (7).

What Are Your Symptoms?

Achieving the most effective results from probiotic intervention requires matching the strain with the symptoms. Further, you need to know what’s driving your symptoms. For example, is diarrhea caused by an intestinal parasite, associated with antibiotics, or induced by radiation treatment? What specific issues do you want to address?


The speed of results will vary depending on your condition. Probiotics can alleviate minor bowel problems pretty quickly, especially diarrhea associated with antibiotic use. More serious issues like chronic gut dysbiosis or immune health require more time. Urinary tract, yeast, and fungal infections usually respond to probiotics immediately.

Knowing whether or not they’re working isn’t always easy to determine because in some cases, symptoms worsen before they get better (isn’t it the law of the universe?). The best way to measure the effects of probiotics on your condition is by journaling. Keep notes on any observable or felt changes in your body, mood, and mental state, as well as including dietary information and probiotic strain and dose if taken irregularly.

We’ll explore this in more detail in a later section, but when selecting a probiotic, ensure it’s high-quality, and manufactured and stored to preserve as much life as possible. Probiotics must reach your gut alive so they can split in two and form a new colony.

Flora Revive 100 from Omnibiotics contains 100 billion CFUs plus 15 live strains featuring DR Caps®, delayed release to maximize survival rate. Taking multiple naturally-occurring flora strains help to populate the digestive tract with beneficial bacteria. Get yours here.

Probiotics For Vaginal Conditions

More than 50 different species of microbes reside in your vagina. One such species called lactobacilli keep it healthy and infection-free.

Many factors can affect a healthy balance of these beneficial microbes. Hormonal changes, particularly estrogen, vaginal pH, and glycogen (the body’s glucose stores) can prevent proper colonization from occurring (8). The menstrual cycle also changes vaginal bacteria (9).

When the balance of bacteria is disrupted, vaginal pH rises and reduces the number of lactobacilli, causing a condition called bacterial vaginosis (BV). While it doesn’t impact other areas of health, BV may affect a woman’s chances of getting pregnant.

How Long Does It Take for Probiotics To Work For BV?


Researchers have found that probiotics such as Lactobacillus (L.) acidophilus can improve symptoms of BV in as little as 30 days by increasing the number of lactobacilli in the vagina.

One randomized trial analyzed 34 healthy women who received encapsulated probiotics by mouth daily for 28 days. Fourteen of the women had asymptomatic BV, and only 40% of the women had normal vaginal flora.

Daily treatment with L. rhamnosus and L. fermentum correlated with healthy vaginal flora in up to 90% of patients. Further, the majority of patients with BV had restored levels of beneficial bacteria within one month of probiotic treatment (10).

In another study, a small group of women with BV were divided into two groups. One group received antibiotics for seven days. Participants in the other group were given antibiotics plus either a probiotic or a placebo for 30 days. After one month, almost 90% of the women in the antibiotic-probiotic group were cured of BV. In contrast, only 40% of women who received antibiotics with a placebo experienced benefits (11).

What a testament to the strength of probiotics. In just one month, these microbial geniuses can restore a healthy balance of vaginal bacteria.

How Long Does It Take for Probiotics To Work For Yeast Infections?

In normal, healthy conditions, fungal growth in the vagina is kept in check by good bacteria. But having too few lactobacilli creates a perfect environment for the growth of a fungus called Candida albicans to overgrow, among other fungi.

Candida is the fungus that causes yeast infections, an uncomfortable condition that causes the vagina to itch and produce a thick, white discharge. Yeast infections are common, but that doesn’t mean they’re normal. Probiotic therapy can help prevent and cure an overgrowth of vaginal yeast.

Yogurt, which contains lactobacillus, is an age-old treatment for yeast infections supported by the scientific community. While consuming sugar-free yogurt regularly can help prevent yeast infections, applying plain, organic yogurt (not the fruity kind please!) as a vaginal cream can have benefits on vaginal health.

In a randomized, triple-blind clinical trial of 70 women with yeast infections, participants were divided into two groups. One group received a vaginal cream composed of honey and yogurt. The other group received clotrimazole, a prescription vaginal cream. Both groups were treated for seven days. Women in the yogurt and honey group showed a significant improvement in symptoms, compared to the women who received the prescription cream (20% versus 8.6%) (12). That means probiotic therapy works better and faster than pharmaceuticals for treating yeast infections.

Based on what we know about the growth time of lactobacilli in response to probiotic intervention, it may be wise to continue treatment for several weeks to avoid fungal regrowth.

The bifidobacterium breve species, also known as B. breve, can help prevent the growth of Candida when taken regularly. It has an antipathogenic effect that also helps ameliorate diarrhea, IBS, and allergies.

Probiotics For Intestinal Conditions

Diarrhea and constipation have various causes, and studies have consistently proven probiotics useful for reducing abdominal bloating, flatulence and relieving gastrointestinal issues. Some strains may also relieve pain. Further, people with functional abdominal pain may experience an improvement in symptoms and overall quality of life (2).

How Long Does It Take for Probiotics to Work for Diarrhea?


Relief from infectious diarrhea can occur as quickly as half a day to two days with probiotic intervention. However, other types may require more time and a regular course of probiotic therapy.

When selecting a probiotic treatment, it’s helpful to know what bacteria are causing intestinal torment. Is it acute diarrhea? Associated with the use of antibiotics? Your body’s response to radiation treatment?

Several studies concluded that specific strains of probiotics can treat various types of diarrhea, including antibiotic-associated diarrhea, Clostridium difficile-associated diarrhea, hepatic encephalopathy, ulcerative colitis, IBS, gastrointestinal disorders, necrotizing enterocolitis (4).

As many as 10 strains and strain combinations can help treat diarrhea, suggesting that probiotic treatment is strain-specific. For example, yogurt containing 10 billion CFUs of L. casei, L. bulgaricus, and S. thermophilus can treat antibiotic-associated diarrhea. L. casei at a twice-daily dose of 1 billion CFUs can effectively treat acute diarrhea (13, 14).

How Long Does It Take for Probiotics to Work for Constipation?

Knowing the underlying cause of your constipation can help you ascertain how quickly probiotic therapy will take effect. Several factors, such as pregnancy, iron supplements, cancer, IBS, and other factors, may require more or less probiotic intervention.


A summary of the research reveals that probiotics may improve constipation in 30 to 60 days, regardless of cause (see 8, 9, 15).

Bifidobacterium species and combinations of Lactobacillus can help improve constipation. Discover more about specific strains for diarrhea and constipation in an upcoming section of this article.

What Factors Influence Probiotic Effectiveness?

Probiotics are delicate creatures. We might regard them as the high priestess of the microbe kingdom. So many variables can affect their survival, and if they do make it to your large intestine, how long they take to work. That’s why selecting the right probiotic for you is so critical.


At first, your body may resist them. Certain probiotics may take longer in some body types, especially those with weak immune systems or poor diets. There must be enough welcoming gut bacteria for the good guys to colonize. You also want to ensure there is a high enough number of CFUs formulated to survive the digestive tract and populate your gut (recommended dose up ahead).

Probiotics may not work if:

  • They’re poor quality
  • You’re taking them with food
  • The strain doesn’t match your symptoms
  • They don’t have a high enough number of CFUs
  • They’re stored incorrectly (i.e. most require refrigeration)

To be effective, probiotics must be able to survive manufacturing, transportation, storage, and your stomach’s hydrochloric acid by the time they reach your large intestine. There should also be strain-symptom congruence and an appropriate dose (16).

Improper storage, such as heat, light, and humidity can rob them of their effectiveness (16). Proprietors only have to label their probiotics with the number of live strains present at the time of manufacture, so it’s common for some strains to be dead by the time they reach your gut.

Your stomach produces hydrochloric acid effective to that of an internal acid torture chamber. That means certain strains will be destroyed before they even make it to your gut. Capsules are better than powders and tablets for withstanding stomach acid, but veggie capsules may not make it unless they have delayed release technology. 

So, if you’re taking a high-quality probiotic with a high number of CFUs that make it through your stomach acid, and you’re not on medication, probiotics should be effective within several minutes of consuming them, particularly if you’re taking them for gastrointestinal issues.

What Probiotic Strains Should I Take & How Much?

Remembering that strain should match the symptom, you need to research what type of probiotic will be most effective for your specific condition before you start probiotic therapy. Some strains can survive until they reach the feces; others perish in the acidic and bilious environment of the GI tract (17). It’s important to note that many brands contain multiple strains. They may prove to be your best bet if you’re unsure about which strain is best for your specific condition.

Dose is another major factor in determining effectiveness. Like strain, dose depends on your symptoms and varies by brand. Many over-the-counter products have a range of CFUs between 1-10 billion per dose. While they may be effective at lower levels, some may require substantially more, depending on the condition you’re treating (2). A minimum of 5 billion CFUs is recommended. OmniBiotics offers 100 billion CFUs and 15 live strains to maximize effectiveness. Learn more about Flora Revive 100 here.

The most common bacteria belong to Lactobacillus and Bifidobacterium species. Along with Saccharomyces, they’re among the most-studied probiotics. Lacto species can exist in the gut for a short time. In contrast, Bifido longum, one of the first species we encountered as babies, can last up to six months, but they’re only effective as long as they’re passing through, which means you have to take them regularly.

B. longum or B. infantis discourages pathogens in the large intestine, helping to prevent diarrhea. L. acidophilus is a safe, popular probiotic found in foods like yogurt, sauerkraut, and kefir that helps prevent diarrhea. It can also help treat small intestinal bacterial overgrowth (SIBO).

Some of the most common strains for treating diarrhea include: Bifidobacterium (B.) bifidum, B. infantis, B. longum, L. rhamnosus, and Streptococcus (S.) thermophilus (3).

For antibiotic-associated diarrhea choose B. lactis, S. boulardii, L. rhamnosus, L. plantarum, L. acidophilus or L. casei. L. casei can also help reduce anxiety (3).

Probiotics that may improve constipation include B. longum, S. cerevisiae, and a combination of L. acidophilus, L. reuteri, L. plantarum, L. rhamnosus and B. animalis (3). Bifidobacterium animalis or B. animalis lactis can improve IBS-associated constipation and diarrhea.

There is a lack of clear guidelines on when and how to use probiotics for effective treatment of different conditions (4). As well, scientists are discovering that many strains may share a common mechanism to resist colonization, so keeping up with current research is imperative for knowing which probiotic is best for you.

Next up, discover more about the best probiotic strains for leaky gut and other GI conditions.

Get Gut Healthy Now

How long does it take for probiotics to work? That depends on a variety of factors. Their most common use is for gastrointestinal issues, such as acute diarrhea. In such cases, you can expect to experience relief in as little as four to six hours. However, more peripheral conditions, like acne, may take longer to heal with probiotics.


The rate at which probiotics have a therapeutic effect depends on strain, dose, quality, storage, your stomach environment, and overall health. Your whole system must be on board when it comes to creating the best possible environment in which to host a proliferation of good gut bacteria. Eating fermented foods, reducing processed foods, and choosing fresh whole nutrients can create the ideal conditions for effective probiotic intervention.

Always consume probiotics on an empty stomach to increase their survival rate and avoid bloating. However, if you’re taking them first thing in the morning, drink plenty of water first to flush out an overly acidic morning stomach. Keep in mind that sugar may impair their ability to survive too.

Probiotic therapy can restore beneficial bacteria in the digestive tract that the body relies on for whole-body health. When we eat high-quality food, we are better able to assimilate nutrients and experience a heightened mood and mental clarity. Indeed, recent research is making fascinating discoveries about the effects of probiotics on psychological health.