Editor's Note
  • May 11, 2018 - For this update, we verified our top picks’ ingredients, third-party certifications, and ratings to ensure that nothing had significantly changed since we wrote the original review. Prices had changed for each product, but there were only minimal ingredient changes — none of which had an impact which products are featured as top picks. One notable change: MegaFood MegaFlora is certified vegan, thereby giving vegan readers another option outside of NOW Foods Probiotic-10, which was featured as the only vegan option in our original review.
  • July 25, 2017 - After further research and expert input, we’ve updated this review with a revised methodology and arrived at a new set of top picks. This time around, we only looked at probiotics vetted by an independent third party. Because supplements aren’t regulated by the Food and Drug Administration (FDA), we wanted to make sure our top picks could live up to their label claims — and didn’t contain any questionable ingredients.

The Best Probiotic Supplements

The best probiotic supplement has multiple strains of effective bacteria in a dosage potent enough to give you results. We researched the ingredient lists of the most popular probiotics from major supplement retailers and found the best supplements for a variety of common issues.

The 4 best probiotic supplements

Best For
General Digestive Health
Islands Miracle Ultra-30 Probiotics
Islands Miracle
This tiny capsule contains nine of the 10 strains recommended for general gut health.
Pros
The right strains to promote gut health
Gluten-free and dairy-free
Cons
Two capsules per serving
Sour smell

Why we chose it

The right strains to promote gut health

If you don’t have a specific health goal in mind and want to bolster the number of good bacteria floating around your system, Dr. Perlmutter recommends starting with a minimum of eight to 10 different bacterial species. He included a core five (L. Plantarum, L. Acidophilus, L. Brevis, B. Lactis, and B. Longum) and we added five more highly researched and universally beneficial strains for a general health pick. Islands Miracle has nine of those 10, plus 30 billion CFUs per serving.

Gluten-free and dairy-free

Because the supplements don’t contain gluten or dairy, they’ll be easy on your stomach. That’s a win if you already have a sensitive digestive system.

Island Miracle Close-up for Probiotic Supplement

Points to consider

Two capsules per serving

Most of the probiotics on our list only require one supplement per serving. If you don’t like swallowing pills, two might feel like an inconvenience.

Sour smell

When we opened the bottle, we noticed a slightly sour smell — common with nearly all the probiotics we tested. It’s subtle, but if you’re particularly sensitive to smell or are wary of stinking up your supplement cupboard, it’s worth considering.

Best For
Immune Health
Renew Life Ultimate Flora Extra Care 30 Billion
Renew Life
This option uses bacteria that can improve upper respiratory infections and aid in the treatment of autoimmune disorders.
Pros
The right strains to improve immune function
Highly accurate labeling
Cons
Big capsules
Cold storage

Why we chose it

The right strains to improve immune function

In addition to the prophylactic effect of stocking your gut with good bacteria, there are some probiotic strains that can improve immune function. Some have even shown promise in treating symptoms of autoimmune disorders.

L. Planatarum and L. Paracasei in particular can improve immune function with as little as 500 million CFUs daily, and a combination of L. Acidophilus and B. Lactis at 2.5 billion CFUs twice daily has been shown to improve upper respiratory infections. Renew Life Flora Extra Care has all four targeted bacteria strains at 30 billion CFUs per serving.

Highly accurate labeling

All our top picks received high scores from Labdoor, but Renew Life earned the highest Label Accuracy score out of all our picks: 87 out of 100. This means chances are good that you’ll get the bacteria and CFUs that the product is advertising — a difficult feat for sensitive bacteria that die off.

Renew Life for Probiotic Supplement

Points to consider

Big capsules

The capsules are a bit bigger than the penny-sized Islands Miracle probiotic, which may be a dealbreaker if you have trouble swallowing pills. If it’s any consolation, though, you only need to take one of the larger pills per day.

Cold storage

It’s worth noting that, like MegaFood MegaFlora, the Renew Life label recommends cold storage — which creates a little more work for you in remembering to take your probiotic.

Unlike MegaFood, the Renew Life label’s cold-storage recommendation is printed so small we nearly missed it (and it didn’t ship with a cold pack). If a probiotic requires refrigeration, be vigilant when buying it — the retailer that stores it or company that ships it should keep it refrigerated until it gets to you. Otherwise, some of its potency may diminish in storage or transit.

Best For
Antibiotic Recovery
MegaFood MegaFlora
MegaFood
This supplement fills your digestive tract with good bacteria until it's fully recovered from an antibiotic course. Plus, it’s vegan.
Pros
The right strains to revamp your microbiome
Vegan
Small capsules
Cons
Cold storage

Why we chose it

The right strains to revamp your microbiome

Antibiotics wreak havoc on your microbiome by decimating both good and bad bacteria. It’s an effective treatment if you have an infection, but without the gut good guys, you’ll come out the other side of any antibiotic treatment with a weaker immune system.

Taking relatively high doses of these probiotic strains before, during, and after antibiotic treatment can help your microbiome get back on its feet: B. Lactis, B. Infantis, L. Acidophilus, L. Casei, L. Bulgaricus, L. Paracasei, L. Rhamnosus GG, and S. Boulardii. Our antibiotic combatant MegaFood MegaFlora has six of these strains, as well as eight others. One serving contains 20 billion CFUs to replenish the good bacteria.

Vegan

MegaFood is our only top pick that’s certified vegan, as well as being gluten- and dairy-free, making it a good choice for any food-sensitive or vegan probiotic-seeker. It has fewer of our wishlist “general health” strains than Islands Miracle, but it still contains five. This could be a go-to if you eat vegan, even if you’re not recovering post-antibiotic.

Small capsules

The capsules are about the length of a pinky fingernail. While these are easy to drop or misplace, they’re also perfect if you have trouble swallowing pills. What’s more, you only have to take one per day.

MegaFood Close-up for Probiotic Supplement

Points to consider

Cold storage

To sustain the life of the CFUs, it’s imperative that you keep this supplement in the fridge. The label indicates it should be stored cold, and it was even shipped to us with an ice pack. If you typically store pills in a pillbox or on the counter, this may make it harder to remember to take your supplement.

Best For
IBS/IBD Relief
Dr. Formulas Nexabiotic Advanced Multi-Probiotic
Dr. Formulas
Research suggests that the bacteria in Dr. Formulas can ease the symptoms of irritable bowel syndrome and acute infectious diarrhea.
Pros
The right strains to improve IBS and IBD symptoms
High Labdoor scores
Cons
Average-sized capsules

Why we chose it

The right strains to improve IBS and IBD symptoms

There has been a lot of research on treating IBS and IBD symptoms with probiotics, much more than on most other pathologies. There are many strains proven to alleviate symptoms — L. Acidophilus and E. Faecium came up again and again in our research.

Dr. Formulas Nexabiotic Advanced Multi-Probiotic has both of these and five other relevant species (with 23 strains total) in its 34.5 billion CFU serving.

High Labdoor scores

This product has the highest overall Labdoor score of our picks at 92.4 out of 100 and the highest score in its “projected efficacy” category at 100 out of 100 – a score “based on a product’s active ingredients, their levels, and their specific biochemical properties. While all of our picks boast strong scores, a 100 out of 100 is a rare gem.

DrFormula Close-up for Probiotic Supplement

Points to consider

Average-sized capsule

Although you only have to take one supplement per day, the capsule itself isn't as small as those from MegaFood. This may be an issue if you have trouble swallowing pills.

Guide to probiotic supplements

How to find the right probiotic supplement for you

Get familiar with bacteria strains

Dr. Michelle Schoffro Cook explained that there’s no single best strain of bacteria, though some strains, like L. Acidophilus or B. Bacterium, have wide-reaching effects. They often act as a starting point from which to add other strains with more specific impacts. Already have probiotics on hand or want to arm yourself with raw knowledge before you shop? The table below shows the research- and expert-backed strains we looked for in each use case:

Know the issue(s) you’re targeting

Our top picks are packed with strains for the most research-supported use cases. While sorting through the most popular probiotics on the market, though, we also found supplements with strains for other, less-researched common use cases:

Probiotic supplement FAQs

Why take a probiotic supplement?

Gut flora makes up 70 to 80 percent of the human immune system. Too much bad bacteria can inflame and destroy intestinal walls, enter the bloodstream, and trigger a multitude of health issues — constipation, depression, skin problems, autoimmune disease, and even bad breath. Adding good bacteria protects the digestive tract from the harmful bacteria in sugars, pesticides, and saturated fats.

How do probiotics work?

Probiotics produce enzymes that help break down chemicals that the average human gut has a hard time with, like the oligosaccharides in legumes. That results in less gastrointestinal distress and better absorption of nutrients. Probiotics also elicit an immune response that helps your body deal with harmful pathogens and other GI problems. The hard research, especially on recommended CFU dosages, is minimal, but it’s expanding as interest in the product does.

Do I need to take prebiotics?

Prebiotics are fuel for the good bacteria (probiotics) in your gut; without prebiotics, probiotics can’t do their job. There are tons of prebiotics in whole fruits and vegetables, including onions, garlic, bananas, asparagus, and artichokes. If you’re worried you’re not getting five to 20 grams per day (a bowl of onion soup), consider taking a prebiotic supplement, usually a powder or drink mix.

Can I get probiotics from food instead?

Some foods are made by adding bacteria — yogurt, pickles, cottage cheese, kombucha, and sauerkraut are good examples. Those foods work to provide the same probiotic benefits as supplements. However, most foods are so processed and pasteurized that it’s unlikely you’ll see the same benefits, let alone the right strains, as you would with a supplement. Regardless, it can’t hurt to get extra probiotics through your diet.

Should I take probiotics regularly, or only when I’m feeling sick?

Probiotics stick around for a while, though for how long isn’t precisely clear. You have to keep taking them to continue to reap the benefits. Further, getting a wide variety of strains into your system is beneficial. “Periodically mixing up your probiotic supplement is also a good way to ensure that you get different health-building strains in your health regime,” says Dr. Cook.

Why do some probiotics require cold storage?

According to ConsumerLabs, heat can kill many probiotic bacteria, while moisture can activate them prematurely (so they die before they get to your gut). The fridge keeps bacteria armored against moisture and heat. Some probiotics are made of freeze-dried organisms, so they don’t need to be refrigerated and usually have a longer shelf-life.

The best probiotic supplements: Summed up

Islands Miracle Ultra-30 Probiotics
Renew Life Ultimate Flora Extra Care
MegaFood MegaFlora
Dr. Formulas Nexabiotic Advanced Multi-Probiotic
The Best for General Digestive Health
The Best for Immune Health
The Best for Antibiotic Recovery
The Best for IBS/IBD Relief
Price (on Amazon)
$28
$14
$45
$15
Supplements per bottle
60
30
90
30
Supplements per serving
2
1
1
1
Number of strains
18
12
14
23
CFUs per serving
30 billion
30 billion
20 billion
34.5 billion
Labdoor Overall Score (out of 100)
70.5
78.6
77.2
92.4
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