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.
How we chose the best probiotic supplements
We started our search with the most popular products from major supplement retailers like Amazon, Drugstore.com, GNC, and Whole Foods. That gave us over 200 supplements. With so many options, we then narrowed our search to 70 probiotics whose purity, potency, and projected efficacy have been vetted by an independent lab like ConsumerLab, Labdoor or the National Science Foundation (NSF). Those labs test — among other things — supplements’ actual composition against labels, verifying that ingredients lists are truthful and that contaminants aren’t present. Because supplement claims aren’t regulated by the Food and Drug Administration (FDA), we wanted to make sure someone was testing if they worked as described.
CFUs — colony forming units — are the number of active live organisms inside the bacteria. According to ConsumerLab, a probiotic should provide at least 1 billion CFUs. One with more stands a better chance at being effective.
That said, supplements with more than 100 billion are only recommended in specific circumstances by your doctor, like if your body doesn’t naturally produce enough probiotics. While there’s little risk of overdose, too much can cause cramps and bloating. We narrowed our search to supplements with dosages between 1 billion and 100 billion CFUs.
Multiple strains of bacteria
Research suggests that probiotics work better as a team. Even pairs are more effective than individuals. Take the strains Lactobacillus Acidophilus and Bifidobacterium Bifidum BB-12, for example. When combined, this duo-force has been shown to help treat a nasty, antibiotic-resistant GI infection. In fact, 75 percent of studies that compared the effect of a strain mixture with a single-strain supplement showed that a mixture was more effective at improving irritable bowel symptoms, immune function, and digestive health.
Selecting a multi-strain probiotic is also consistent with the theory that filling your gut with enough good bacteria outcompetes any bad bacteria for the same space and resources. In your gut, the more diversified the good bacteria, the harder it is for the baddies to gain a foothold. With all this in mind, we only looked at supplements containing multiple strains of bacteria.
In addition, we wanted supplements with bacteria strains that have the most evidence of being truly effective. We dug through probiotic studies from the National Center for Biotechnology Information, dissected ConsumerLab’s extensive report, and verified those findings with our experts.
We found the most evidence linking strains to antibiotic recovery, immune health, and IBS/IBD relief. We made checklists of the most researched strains that treat those issues (10 strains known to boost general health, six for immune health, seven for antibiotic recovery, and seven for IBS/IBD relief) and dug into ingredients lists to find the supplements containing the highest number of effective strains for each use case.
We also found strains linked to five other health benefits like weight loss and lowering cholesterol. We feature options for those cases below, but they aren’t top picks because those use cases aren’t as heavily researched as immune health or IBS relief. Still, any probiotic supplement is going to make some improvement on your digestive health, so don’t be afraid to experiment.
Bacteria die out over time. Some supplements list the potency when they was manufactured (before they rode in a truck, sat on the shelf at the grocery store, or hung out in the kitchen cupboard for a few months). In this case, there may be dramatically fewer viable bacteria by the time you consume them than when they were first encapsulated, and good bacteria are no good to you dead.
The best probiotic manufacturers will list their potency (in CFUs) at the time of expiration, ensuring that you get the dosage you’re paying for. Dr. David Perlmutter, board-certified neurologist, American College of Nutrition Fellow, and author of The New York Times best-sellers Brain Maker and Grain Brain puts it this way: “Avoid products that indicate a specific number of bacteria ‘at the time of manufacture,’ and instead look for products that, like other supplements, have a shelf-life.” Each of our top picks lists a specific “best by” or “expires on” date clearly on its bottle.
The 4 best probiotic supplements
- Islands Miracle Ultra-30 Probiotics -
Best for General Digestive Health
- Renew Life Ultimate Flora Extra Care 30 Billion -
Best for Immune Health
- MegaFood MegaFlora -
Best for Antibiotic Recovery
- Dr. Formulas Nexabiotic Advanced Multi-Probiotic -
Best for IBS/IBD Relief
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.
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.
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.
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.
Points to consider
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.
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.
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.
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.
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.
Points to consider
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.
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.
Points to consider
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:
|Beneficial Strains||Our Top Picks|
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:
- 21st Century Ultra Potency Advanced Probiotic -
Best for Anxiety and Allergies
- Nature’s Way Primadophilus Fortify Women’s Probiotic -
Best for Weight Loss
- Advocare Probiotic Restore Ultra -
Best for Lactose Intolerance
- Garden of Life Dr. Formulated Probiotics Once Daily Women’s -
Best for Lowering Cholesterol
- Hyperbiotics PRO-15 Advanced Strength -
Best for Women's Health
- NOW Foods Probiotic-10 -
Another Vegan Option (see MegaFood for another vegan go-to)
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.