Probiotics are among the most popular of all dietary supplements, and sales continue to skyrocket each year. By 2023, probiotic supplement sales are projected to exceed 64 billion dollars (1).

People may take probiotics because they’ve heard they can help reduce symptoms of certain medical conditions, boost immune health, improve depressive symptoms, and even promote weight loss.

But are probiotics really effective? Should everyone be taking a probiotic?

If you and your healthcare team decide that you may benefit from taking a probiotic supplement, there are many excellent products on the market to choose from.

Depending on your needs, you may want to choose a single or multi-strain probiotic. If you’re unsure about the type of probiotic or dosage that you should be taking, ask a healthcare professional for advice.

This article explains what probiotic supplements are, who may benefit from taking one, how to choose the right kind, and our picks of the 9 best products on the market.

Probiotics are defined as “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host” (1).

Probiotics are found naturally in certain foods and in your gut. For example, foods such as kimchi, fermented yogurt, and sauerkraut can be natural sources of probiotics. Probiotics can also be added to foods during processing.

Beneficial bacteria live in your intestinal tract and participate in a variety of important bodily processes, such as vitamin production, mood regulation, digestion, immune function, and more (2).

Probiotics can also be taken as supplements, which contain high doses of a single probiotic strain or multiple probiotic strains (3).

Probiotic supplements have been linked to some health benefits. But while research on probiotics has increased significantly over the past 20 years, researchers are still learning about probiotics and the health effects of probiotic supplements.

What are CFUs?

Probiotics are measured in colony-forming units (CFUs). These units represent the number of viable bacteria per dose.

Products labeled as 1 x 109 CFU contain 1 billion viable or live bacteria per dose. Most supplements contain 1–10 billion CFUs per dose. However, some supplements contain much higher amounts.

To confer beneficial effects, probiotics must be taken in quite large doses. Researchers suggest that probiotics must contain at least 106 (1 million) viable CFUs per gram to be able to survive digestion and exert positive effects in the body (4, 5).

If you’re interested in taking a probiotic supplement, it’s important to first determine whether a probiotic supplement is necessary for your specific health needs.

If you’re instructed to take a probiotic, please consider the following:

  • Probiotic strains. Probiotics are not one-size-fits-all remedies, and certain probiotic strains are much more effective for certain medical conditions and symptoms than others. Look for supplements with specific strains based on your needs.
  • Intended use. The effectiveness of probiotic supplements is not only strain-specific but also disease-specific, meaning the correct strain and dose must be appropriate for the condition or symptom intended to be treated (6).
  • Brand. Manufacturing processes, the shelf life, and the formulation type can significantly affect a probiotic supplement’s effectiveness. As such, purchasing probiotics from established, physician-trusted brands is essential (6).
  • Storage requirements. Some probiotics require refrigeration. Check the product label for proper storage instructions. In general, probiotics are sensitive to heat. Thus, if they don’t require refrigeration, you’ll want to store them in a cool, dry area.
  • CFUs. The product quality matters. It’s important to look for probiotics that contain at least 106 (1 million) CFUs per gram, as research suggests that this is the minimum amount needed to exert positive effects in the body (4, 5).

Also keep in mind that because probiotics are quite vulnerable to factors like temperature change and storage time, many may no longer be viable by the time the product is purchased.

For this reason, the National Institutes of Health (NIH) recommends that customers choose products that include CFUs at the end of a product’s shelf life, which indicates that a product contains a therapeutic number of CFUs after the product is purchased (3).

We selected the best probiotics using the following criteria:

  • Vetting. All the products have been vetted to ensure that they meet Healthline’s medical and business standards. You can read more about our vetting process here.
  • Effective dose. All of the supplements below contain at least 106 (1 million) CFUs per gram.
  • Ingredients. We looked for products that are made from high quality ingredients and free of artificial additives and fillers.
  • Personal needs. Whether you need a specific probiotic strain or follow a gluten-free diet, we included options to suit a variety of needs and preferences.

A note on price

General price ranges with dollar signs ($–$$$) are indicated below. One dollar sign means the product is rather affordable, whereas three dollar signs indicate a higher cost.

Generally, prices range from $0.42–$1.33 per serving, or $18.49–$32.99 per container, though this may vary depending on where you shop.

Pricing guide:

  • $ = under $0.50 per serving
  • $$ = $0.50–$1 per serving
  • $$$ = over $1 per serving

Note that the dosage recommendations vary between 1–2 capsules or tablets, taken 1–2 times daily.

Thus, a product that you need to take fewer times per day may be comparatively cheaper, despite having a higher price per count than a product you need to take multiple times per day.

Best overall probiotic supplement

Culturelle Digestive Daily

  • Price: $$
  • Serving size: 1 capsule per day
  • CFU count: 10 billion
  • Strains: Lactobacillus rhamnosus GG

One capsule of Culturelle Digestive Daily probiotic has 10 billion CFUs of Lactobacillus rhamnosus GG, a probiotic strain that may benefit a number of health conditions like diarrhea and irritable bowel syndrome (IBS), plus 200 mg of the prebiotic inulin, which fuels beneficial gut bacteria (7).

​​Culturelle guarantees that the stated number of CFUs on the box is viable through the expiration date of the product, something the NIH recommends customers look out for.

Culturelle products are packaged to maintain viability, and the company is certified through NSF International, an organization that independently tests supplements for quality and potency and inspects manufacturing facilities.

Culturelle products don’t require refrigeration.

Pros

  • may be good for diarrhea and IBS
  • doesn’t require refrigeration
  • gluten-free
  • dairy-free
  • third-party tested

Cons

  • may not be suitable for those following a vegan diet

Best probiotic supplement for IBS

Align Probiotic Extra Strength

  • Price: $$$
  • Serving size: 1 capsule per day
  • CFU count: 5 billion
  • Strains: Bifidobacterium longum 35624

Align is a physician-trusted brand that contains Bifidobacterium longum 35624, formerly known as Bifidobacterium infantis 35624, a probiotic strain that has been researched for its role in digestive health, including IBS symptoms (8).

This product’s label states that each capsule contains 5 billion live bacteria at the time of manufacturing and 50 million CFUs until the “best by” date.

As it doesn’t require refrigeration, it’s a good option if you frequently travel or prefer not to worry about storing your probiotic supplement in the fridge.

Note that Align contains trace amounts of lactose, so it may not be appropriate for those with severe lactose intolerance.

Pros

  • travel-friendly
  • formulated to relieve digestive issues

Cons

  • may not be appropriate for those with lactose intolerance
  • not suitable for vegan diets
  • expensive

Best shelf-stable probiotic supplement

Bio-Kult

  • Price: $
  • Serving size: 2 capsules, taken once or twice per day
  • CFU count: 2 billion
  • Strains: Bacillus subtilis, Bifidobacterium bifidum, Bifidobacterium breve, Bifidobacterium infantis, Bifidobacterium longum, Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus casei, Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus helveticus, Lactobacillus salivarius, Lactococcus lactis subsp. lactis, Streptococcus thermophilus

Bio-Kult contains 14 probiotic strains, including Lactobacillus acidophilus, Streptococcus thermophilus, and Bifidobacterium longum.

Each Bio-Kult capsule contains a minimum of 2 billion microorganisms, and Bio-Kult guarantees that the total bacteria count of their products is viable until the end of the product’s shelf life.

Each probiotic strain in Bio-Kult is microencapsulated and individually freeze-dried, which protects the probiotics from stomach acid and allows the product to be stored at room temperature.

Bio-Kult products are third-party tested by United Kingdom Accreditation Service accredited labs.

Bio-Kult is not appropriate for those with a severe allergy to milk proteins, but it is safe for those with lactose intolerance.

Pros

  • stored at room temperature
  • relatively affordable
  • suitable for all ages
  • third-party tested

Cons

  • not appropriate for those with severe allergy to milk proteins
  • not suitable for vegan diets

Best affordable probiotic supplement

Jarrow Formulas Jarro-Dophilus EPS

  • Price: $
  • Serving size: 1 capsule per day
  • CFU count: 5 billion
  • Strains: Lacticaseibacillus rhamnosus, Lactobacillus helveticus, Pediococcus acidilactici, Lacticaseibacillus casei, Bifidobacterium longum, Lactiplantibacillus plantarum, Bifidobacterium breve, Lactococcus lactis subsp. lactis

Jarrow Formulas Jarro-Dophilus EPS contains 8 probiotic species from 6 genera, including, Lactobacillus, Bifidobacterium, Lacticaseibacillus, Lactiplantibacillus, Lactococcus, and Pediococcus.

The capsules have an enteric coating, which is a barrier that helps minimize degradation in the stomach.

Some studies show that enteric-coated probiotics are more effective than nonenteric-coated probiotics. A 2019 study found that enteric coating led to a 20‐ to 40‐fold increase in the delivery of viable probiotics to the small intestine (9).

When stored properly — at room temperature, in a cool, dry environment — the 5 billion CFU count per capsule is guaranteed through the “best used before” date.

Jarrow Formulas products are tested by third-party labs that are accredited by the U.S. Department of Agriculture.

Pros

  • no refrigeration necessary
  • third-party tested
  • relatively affordable

Cons

  • not suitable for vegan diets

Best dairy-free probiotic supplement

Garden of Life Dr. Formulated Probiotics Once Daily 30 Billion CFUs

  • Price: $$$
  • Serving size: 1 capsule per day
  • CFU count: 30 billion
  • Strains: Lactobacillus acidophilus, Lactobacillus plantarum, Lactobacillus gasseri, Lactobacillus paracasei, Lactobacillus bulgaricus, Lactobacillus brevis, Lactobacillus casei, Lactobacillus rhamnosus, Lactobacillus salivarius, Bifidobacterium lactis, Bifidobacterium bifidum, Bifidobacterium breve, Bifidobacterium infantis, Bifidobacterium longum

Garden of Life Dr. Formulated Probiotics Once Daily 30 Billion CFUs provides 30 billion CFUs of 14 probiotic strains, including Bifidobacterium lactis, Lactobacillus acidophilus, and Lactobacillus casei.

Garden of Life guarantees the CFU count through the end of the product’s “best use” date when stored properly. This supplement keeps best in the refrigerator.

This product is dairy-free and makes a good choice for those with lactose intolerance.

While it’s also made without peanuts, tree nuts, shellfish, and soy products, the supplement is manufactured in a facility that handles major allergens, so it may not be a good option if you have a severe food allergy.

Pros

  • CFU count guaranteed through “best use” date when product is stored properly
  • dairy-free

Cons

  • not suitable for travel, as it requires refrigeration
  • expensive
  • not vegan-friendly

Best allergen-friendly probiotic supplement

NOW Probiotic-10 25 Billion

  • Price: $$
  • Serving size: 1 capsule, taken once or twice per day
  • CFU count: 25 billion
  • Strains: Lactobacillus acidophilus, Bifidobacterium lactis, Lactobacillus plantarum, Lactobacillus casei, Lactobacillus rhamnosus, Lactobacillus paracasei, Bifidobacterium breve, Streptococcus thermophilus, Lactobacillus salivarius, Bifidobacterium longum

NOW Probiotic-10 25 Billion is a blend of 10 probiotics inducing Lactobacillus acidophilus, Bifidobacterium lactis, and Lactobacillus rhamnosus, many of which have been shown to support immune health (10).

This product is formulated to deliver a potency of at least 25 billion CFUs through the “best by” date.

NOW uses DNA-fingerprinting technology to guarantee the identity, potency, and purity of the bacterial strains used in its probiotic products. This testing also helps identify potential bacterial contaminants in the products prior to manufacturing.

Additionally, NOW is certified by Underwriters Laboratory, an independent certification safety company that tests products to ensure they meet strict purity and quality standards.

This probiotic is also suitable for those with allergies as it’s processed in an allergen-free facility.

Pros

  • processed in an allergen-free facility
  • third-party tested
  • delivers a potency of at least 25 billion CFUs through the “best by” date
  • uses DNA-fingerprinting technology
  • may support a strong immune system

Cons

  • not suitable for vegan diets

Best pre and probiotic supplement

Klaire Labs Ther-Biotic Pro IBS Relief

  • Price: $$$
  • Serving size: 1 capsule, taken once or twice per day
  • CFU count: 20 billion
  • Strains: Lactobacillus acidophilus, Bifidobacterium lactis, Lactobacillus plantarum

Klaire Labs Ther-Biotic Pro contains a blend of probiotics and a prebiotic.

Specifically, it contains Lactobacillus and Bifidobacterium probiotic strains, both of which have been shown to help relieve IBS-related symptoms such as abdominal pain, constipation, and diarrhea, though more research is still needed (8, 11, 12).

Also included is partially hydrolyzed guar gum, a prebiotic that feeds the good bacteria in the gut. A 2016 study found that 6 grams of partially hydrolyzed guar gum was effective in reducing bloating associated with IBS over the course of 18 weeks, but more research is needed (13).

This product is free from common allergens, though it’s unclear whether there’s a risk of cross contamination.

Additionally, the supplement doesn’t require refrigeration, though storing it in the refrigerator may extend its shelf life.

Klaire Labs products are processed in a facility that follows the current good manufacturing practices put in place by the Food and Drug Administration and is certified by NSF International.

Pros

  • contains probiotics and prebiotics
  • contains strains that may help IBS symptoms
  • no refrigeration required
  • free from allergens
  • third-party tested

Cons

  • expensive
  • not suitable for vegan diets

Best probiotic supplement for athletes

Thorne FloraSport 20B

  • Price: $$$
  • Serving size: 1 capsule, taken once or twice per day
  • CFU count: 20 billion
  • Strains: Lactobacillus acidophilus, Bifidobacterium lactis, Lactobacillus paracasei

Thorne FloraSport 20B contains 20 billion CFUs from 3 probiotic strains. It’s formulated specifically for individuals under stress, such as athletes, as it’s meant to support both the digestive and immune systems.

While exercise has many benefits, engaging in regular high intensity workouts can take a toll on your body’s immune response (14).

This probiotic from Thorne contains Lactobacillus acidophilus and Bifidobacterium lactis, both of which have been shown to support immune health and could be beneficial for athletes and active individuals (10).

Refrigeration isn’t required, as the capsules are packaged in temperature-resistant blister packs, making this a great option for traveling.

Additionally, this probiotic supplement is certified gluten-free and NSF Certified for Sport.

Pros

  • packed in temperature-resistant blister packs (no refrigeration required)
  • formulated for athletes, active individuals, and travelers
  • NSF Certified for Sport

Cons

  • expensive
  • may not be suitable for those following a vegan diet

Best probiotic supplement for diarrhea

Florastor Daily Probiotic for Women and Men

  • Price: $$
  • Serving size: 2 capsules, taken once or twice per day
  • CFU Count: 5 billion
  • Strains: Saccharomyces boulardii

Florastor Daily Probiotic provides 5 billion CFUs of Saccharomyces boulardii, a probiotic yeast that may be effective in managing symptoms of inflammatory bowel disease (IBD).

The strain has also been shown to help with diarrhea, especially antibiotic-associated or acute diarrhea (15, 16).

Florastor Daily Probiotic has a 4.8/5-star rating on Amazon and more than 6,000 total reviews. Customers note that the probiotic is effective for reducing gas and bloating, though many also feel that it’s a bit too expensive.

The supplement comes in a vegetarian capsule and is non-GMO and gluten-free. However, because it contains lactose, it’s not suitable for those who are allergic to dairy.

Florastor products are third-party tested by Labdoor.

Pros

  • high customer rating
  • no refrigeration required
  • third-party tested

Cons

  • not appropriate for those with an allergy to milk proteins

Here’s a quick look at how our top picks compare:

Price rangeServing sizeCFU countRefrigeration neededGood for
Culturelle Digestive Daily$$1 capsule10 billionnogeneral digestive health
Align Extra Strength$$$1 capsule5 billionnomanaging IBS symptoms
Bio-Kult$2 capsules2 billionnogeneral digestive health
Jarrow Formulas$1 capsule5 billionnogeneral digestive health
Garden of Life$$$1 capsule30 billionyesthose who need a dairy-free probiotic
NOW Probiotic-10$$1 capsule25 billionno• immune health
• digestive health
Klaire Labs Ther-Biotic Pro$$$1 capsule20 billionnomanaging IBS symptoms
Thorne FloraSport 20B$$$1 capsule20 billionno• athletes
• immune health
• digestive health
Florastor Daily Probiotic$$2 capsules5 billionnodiarrhea

Probiotic supplements have been shown to benefit health in a number of ways.

However, some of the purported benefits of probiotics aren’t supported by research, so it’s important to always consult a healthcare professional before taking a probiotic supplement, especially if you’re hoping to improve symptoms related to a health condition.

May improve symptoms of certain gastrointestinal diseases

Some of the most well-studied uses of probiotic supplements relate to the treatment of gastrointestinal diseases like IBS and IBD.

In one review of 11 studies, 7 of the studies reported significant improvements in symptoms like bloating and abdominal pain in people with IBS who took probiotic supplements, compared with a placebo. The remaining four studies didn’t find significant improvements.

The review also found that multi-strain probiotics used for at least 8 weeks were the most effective for improving IBS symptoms (11).

Notably, Lactobacillus acidophilus was present in all of the multi-strain supplement studies that reported significant improvements (11).

Multi-strain probiotics may improve some symptoms in those with IBD, though they appear to be less effective for people with Crohn’s disease. However, evidence is currently limited, and well-designed studies are needed (17, 18, 19).

May help with constipation and diarrhea

Studies indicate that probiotics may help improve multiple types of diarrhea, including infectious diarrhea, antibiotic-associated diarrhea, and traveler’s diarrhea (20, 21, 22).

Certain strains, including Lactobacillus rhamnosus GG and Saccharomyces boulardii, seem to be particularly effective for treating diarrhea in children and adults (15, 16).

Some probiotics, such as ​​Bifidobacterium lactis, may also help improve constipation. However, study results vary, with some showing no improvements in constipation with probiotic treatment (23).

May benefit urinary health

Supplementing with probiotics may help maintain urinary tract health and be beneficial for women who get frequent urinary tract infections (UTIs) (24).

Some studies show that treatment with the probiotics Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 may help reduce UTIs in women (25, 26).

However, study results are conflicting.

One review of three randomized controlled trials found that taking probiotics didn’t significantly reduce UTI recurrence in postmenopausal women (27).

Other potential benefits

In addition to the benefits listed above, some research suggests that probiotic supplements may have the following effects:

  • May promote immune health. Evidence supports the role of probiotic supplements in maintaining immune health. Several studies suggest that probiotics may enhance immune function in certain populations, but more research is needed (28, 29, 30).
  • May benefit metabolic health and weight management. Alterations in gut bacteria may contribute to obesity and metabolic issues, and some studies have shown that probiotic supplements may promote weight loss. Research in this area is ongoing (31).
  • May improve cardiovascular risk factors. Probiotic supplements may help reduce blood lipid levels in some people, which may decrease the risk of heart disease. However, evidence is limited at this time (32, 33, 34).
  • May help treat certain mood and emotional disorders. Studies suggest that certain probiotics may help treat depression, but more high quality studies are needed before strong conclusions can be made (35, 36).

Contrary to popular belief, probiotic supplements are not necessary or appropriate for most people.

Not only can they be expensive, but they may lead to side effects like bloating and bacterial overgrowth. Plus, they could lead to excessive immune stimulation and infection among people with weakened immune systems (37, 38).

While some people, including those with IBS and certain types of IBD, may benefit from specific strains of probiotics, in general, most healthy people who follow a nutritious diet and healthy lifestyle do not need to take probiotic supplements.

What’s more, some researchers are concerned that the widespread use of probiotics may lead to antibiotic resistance and warn that many studies investigating the safety and efficacy of probiotics are of poor quality (39).

For these reasons, it’s not a good idea to take probiotics before consulting a healthcare professional. They can help you decide whether a probiotic supplement is appropriate and give brand and dosage recommendations.

You may be considering a probiotic supplement if you’re experiencing gut issues. But it’s a good idea to schedule an appointment with a healthcare professional first, because your symptoms could be related to a condition that requires a specific treatment or medication.

Additionally, taking a probiotic can do more harm than good in some individuals, so it’s important to discuss options with a trusted expert before trying anything new (37, 38).

What is the most effective probiotic supplement?

The most studied and used strains of probiotics are Lactobacillus and Bifidobacterium (2).

However, probiotic supplements are strain- and disease-specific, so the most effective strain will depend on the condition or issue that the supplement is meant to improve (6).

Is it OK to take a probiotic every day?

Because research on the safety and effectiveness of probiotics in people without existing health conditions is still inconclusive, it’s best to talk with a healthcare professional before starting a daily probiotic (39).

What are the signs you need probiotics?

Research suggests that probiotics may help improve symptoms associated with IBS and IBD.

If you’re experiencing gastrointestinal symptoms, such as abdominal pain, bloating, cramping, diarrhea, and constipation, or have received a diagnosis of IBD or IBS, you may benefit from a probiotic (11).

Still, you should first meet with a healthcare professional to discuss your options and determine whether a probiotic is a good fit for you.

If you could benefit from a probiotic, they can help you choose the right strain or strains and suggest a dosage depending on your medical history and symptoms.

Probiotic supplements may help those with certain conditions, such as IBS, constipation, and urinary tract infections.

However, probiotics aren’t necessary for everyone, and the effectiveness of probiotic supplements depends on the strain, dosage, and condition being treated.

Note that probiotics are not one-size-fits-all remedies, and it’s best to work with a healthcare professional to determine whether a probiotic supplement is the right choice for your health needs.

Finally, there are many other ways to take care of your gut microbiome and overall health that don’t involve dietary supplements.

Following a nutrient-dense diet, managing your stress levels, getting enough sleep and exercise, and maintaining a healthy body weight are much more important for your health than taking any one supplement.