Probiotics have been in the spotlight for years, thanks to their essential role in gut health and overall wellness. Not only do these live bacteria improve your immune system, digestion, and heart health, but many people have started using probiotics for weight loss.

These microorganisms naturally live in your body and are designed to maintain beneficial bacteria in the intestines, says Katherine Saunders, MD, an obesity medicine physician and co-founder of Intellihealth.

A healthy balance of good bacteria in the body may help ward off a range of health issues, adds Frances Largeman-Roth, RDN, the author of Eating in Color. That include digestive problems like irritable bowel syndrome (IBS), skin diseases like atopic dermatitis, and even the common cold, per the National Center for Complementary and Integrative Health (NCCIH).

But when it comes to weight loss, the benefits of probiotics are not as clear. “In theory, probiotics could alter the microbiome in a positive way, however, studies have illustrated minimal if any weight loss,” explains Dr. Saunders. “There are so many bacterial strains in our intestines and so much we don't know about what happens when the balance is altered.”

Meet the experts: Katherine Saunders is an obesity medicine physician and co-founder of Intellihealth. Caroline Apovian is the director of nutrition and weight management at Boston Medical Center. Frances Largeman-Roth is a nutritionist and the author of Eating in Color.

First things first, what do probiotics do?

Probiotics can improve your health by maintaining or restoring the balance of good to bad bacteria in the gut microbiome, like if there's been an imbalance, say, after taking antibiotics.

“Good bacteria can support health and immune function by helping our body digest food, produce vitamins, break down and absorb medications, and prevent overgrowth of bad bacteria that can make us sick,” says Dr. Saunders.

Can probiotics help with weight loss?

Honestly, no one knows for sure—because most probiotic research has focused on how to improve digestive or immune health.

The most promising evidence on probiotics and weight loss comes from a 2013 study in The British Journal of Nutrition, which looked at the effects of one strain of probiotics, Lactobacillus rhamnosus (LGG). At the end of the trial, the women who took probiotics lost more weight than those in the placebo arm. The probiotics group also went on to continue losing weight after the trial had ended (while the placebo group only maintained).

That sounds legit, right? Well...kind of. The difference in weight loss between the probiotic and placebo groups in this study just barely qualifies as noteworthy, says Caroline Apovian, MD, the director of nutrition and weight management at Boston Medical Center.

“There was no weight loss difference overall between the probiotic and placebo groups,” she says, “but there was a significance when you separate out the women in the probiotic group.” Even then, Dr. Apovian notes, the women in the probiotic group only lost about 1.8 kilograms (or just under four pounds) more than the placebo group.

Probiotics may have the potential to aid in weight loss and decrease fat mass in those who are overweight or obese, according to a 2021 review published in Nutrients. However, the studies included also put participants on a calorie-restricted diet and ramped up their physical activity. So the weight loss observed was not solely related to probiotics.

There is no real evidence on which probiotic strains might work best for weight-loss results.

That said, the gut microbiome definitely plays some role in weight management. There are distinct bacterial levels in obese individuals compared to those with a normal body mass index, a 2018 study published in the International Journal of Endocrinology found.

“Different environmental and dietary factors can alter the microbiome in ways that can increase inflammation and affect metabolism and digestion,” says Dr. Saunders. That's why some people are more likely to gain weight if their microbiome is imbalanced.

In a 2021 study published in the mSystems Journal, researchers found that if you have genes in your gut that makes weight loss more difficult, you can alter your diet to shift your gut microbiome and make it easier to lose weight.

Plus, probiotics promote overall health, which never hurts when it comes to weight loss. “Gut bacteria lines the intestines and comes in contact with the food you eat, [so] the thought is that this may impact how you absorb nutrients,” says Amy Gorin, RDN, the owner of Amy Gorin Nutrition in the New York City area.

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It’s important to remember, though, that exactly how probiotics for weight loss may work is an educated guess at best—it's unclear if or why there's a connection. While it’s entirely possible that a probiotic-filled healthy gut could be more amenable to weight loss or weight maintenance, it also might be thanks to another kind of cause and effect, Dr. Apovian adds.

“It may certainly be that those people who eat healthy have healthier guts and not the other way around,” she says. “As far as which came first, the healthy diet or the healthy gut, it’s likely the healthy diet.”

preview for Probiotics vs. Prebiotics Explained

So...how can I add more probiotics to my diet?

While you can get probiotics through food, the easiest way to get some probiotics in your diet every day without fail is likely through a probiotic supplement.

But here's the thing: There are dozens of probiotic supplements on the market, with different ones containing different strains. Unfortunately, the few studies that have been done so far offer no real evidence about which probiotic strains might work best for weight-loss results, according to Dr. Apovian. In the 2013 British study, LGG was chosen—but why? “They just picked one!” she says.

One study in Obesity found daily supplementation with the brand VSL#3 may provide some protection against weight gain when eating a high-calorie, high-fat diet. However, the sample size was limited: only 20 non-obese men were studied.

Similarly, a 2013 study published in the Journal of Functional Foods found a link between loss of body fat and the probiotic strains Lactobacillus fermentum and Lactobacillus amylovorus (3 percent and 4 percent, respectively), but only 28 participants were studied.

If you still want to experiment with probiotics for weight loss, though, Gorin says to hit up your doctor for the go-ahead before taking any supplements—while probiotics are generally considered to be safe, they may cause some gastrointestinal upset at first, like bloating and gas.

Here are a few tips on how to select a high-quality probiotic supplement for weight loss, according to Ehsani:

  • If its third-party certified, it's likely a good supplement. Supplements don’t go through rigorous testing nor do they have to, so you can’t be sure you are getting a high-quality product. Look for the NSF-certified seal or USP-certified mark on the label.
  • Check whether the product contains the most common strains such as Lactobacillus, Bifidobacterium, and Saccharomyces.
  • Note that higher CFU counts do not necessarily mean it's better for you or will lead to faster results. It really depends on the specific microorganisms it contains rather than the number of them.
  • Different strains of bacteria have different health benefits too, such as LGG may help with antibiotic-associated diarrhea, while Lactobacillus gasseri and Lactobacillus rhamnosus may be most effective to aid with weight loss.

It's always ideal to check with your doctor before starting any supplement. Once you get the green light, you can try any of the following (and check out the pros and cons from Ehsani):

The Best Probiotics That Nutritionists Recommend
MegaFlora Probiotic Supplement
MegaFood MegaFlora Probiotic Supplement
$38 at Amazon
Pros
  • Contains 14 strains of probiotics, with 20 billion active bacteria
  • Cheaper than some products on the market
  • Soy- and dairy-free
  • Vegan-friendly
Cons
  • Not a great on-the-go option because it has to be refrigerated
  • Has to be taken with meals

Megafood supplements are made from real whole foods and are gluten-, soy-, and dairy-free. "The brand has third-party certifications from NSF and high standards surrounding supplement ingredients, sustainability, quality, and transparency,” says Jonathan Valdez, RDN.

Raw Probiotics Ultimate Care
Garden of Life Raw Probiotics Ultimate Care
Pros
  • Doesn’t require refrigeration
  • Contains 100 billion CFU and 34 probiotic strains
  • Made from raw fruits and veggies
Cons

    This whole-food probiotic formula emulates eating fermented food. "Raw probiotics maintain more live nutrients, enzymes, and probiotic strains, and offer targeted health benefits," says Valdez.

    Primal Defense Ultimate Probiotic Formula
    Garden of Life Primal Defense Ultimate Probiotic Formula
    Now 18% Off
    Pros
    • Contains 15 billion CFU probiotic and 13 different probiotic strains
    • Geared towards supporting a healthy immune system
    • Contains 10% daily value for iron
    Cons
    • The iron could cause constipation

    "This supplement is a high-potency, broad-spectrum probiotic formula encompassing a blend of strains to support bowel function and maintain a healthy immune system,” says Valdez.

    Probiotics With Prebiotics
    Probiotics With Prebiotics
    Now 12% Off
    Pros
    • Cheaper than most products
    • Works well for sensitive stomachs
    • Contains prebiotics
    Cons
    • Has fewer probiotic strains than other products

    This vegan, plant-based probiotic supplement helps aid optimal digestive health, immune function, mood balance, as well as hair and skin health, according to Valdez.

    Nordic Flora Probiotic Daily
    Nordic Flora Probiotic Daily
    Pros
    • Cheaper than most other probiotics
    • Vegan-friendly
    • Allergen-free
    Cons
    • Pill form may not be as attractive to some people

    This supplement is a blend of four probiotic strains, with 12 billion live cultures and prebiotics for digestive wellness and immune support.

    Probiotic Medical Food
    VSL #3 Probiotic Medical Food
    Pros
    • Has been tested in research
    • Contains a very high potency of bacteria
    • Kosher- and halal-certified
    Cons
    • May cause gas, bloating and abdominal discomfort

    VSL #3 is another probiotic supplement that's more potent than most (it contains eight different strains of live bacteria!). It’s often prescribed along with certain medications to manage chronic digestive issues.

    Advanced Gut Health Probiotic
    Advanced Gut Health Probiotic
    Pros
    • Cheaper than most other products
    • Contains Lactobacillus gasseri and Lactobacillus rhamnosus, two strains specifically studied for weight loss
    • Comes in delayed release capsules
    Cons
    • Not third party-tested

    “This product contains Lactobacillus gasseri and Lactobacillus rhamnosus, both of which might help a person lose weight,” says Roxana Ehsani, RD.

    Ultimate Flora Extra Care Probiotics
    Ultimate Flora Extra Care Probiotics
    Now 35% Off
    Pros
    • Good for digestive support
    • One of the cheapest probiotics
    Cons
    • Needs to be refrigerated

    This supp contains 30 billion live cultures from 12 different strains, and contains both Bifidobacterium and Lactobacilli blends.

    Pro Strength Daily Probiotic
    Culturelle Pro Strength Daily Probiotic
    Pros
    • Contains prebiotics
    • Contains one of the most studied LGG probiotic
    Cons
    • May cause extra gas and bloating
    • Not vegan-friendly

    Culturelle specifically advertises that it uses the LGG strain, which has been studied for its relationship to weight loss.

    Are there any risks to using probiotics for weight loss?

    Any weight loss will be minimal, says Dr. Saunders, and you could even throw off the bacterial balance in your gut, which may lead to digestive issues such as gas, bloating, or an upset stomach.

    “Few safety concerns have been identified with probiotics, but I wouldn't recommend them for weight loss until I see convincing evidence of efficacy, safety, and tolerability,” she notes. “I don't recommend probiotics for weight loss, but anecdotally my patients who've tried them generally haven't experienced significant side effects. More importantly, they haven't experienced weight loss either.”

    And there are some people who should stay away from probiotics. "Anyone who has a compromised immune system or certain diseases may get sick from taking probiotics," says Ehsani. "Anyone on antibiotics may not be able to benefit from using probiotoics, as some antibiotics prevent them from working well."

    Some probiotics may cause bloating, gas, or belching in general for some people, which may be uncomfortable, Ehsani adds.

    What if I don't want to take a supplement? Can I get probiotics anywhere else?

    You sure can—in fact, it might be better to get your probiotics from food sources. “I would always urge people to eat food first," says Gorin—that way, you're getting other nutrients too, in addition to probiotic benefits.

    Dr. Apovian agrees, saying that most probiotic foods are healthy foods and it certainly can’t hurt to eat them (which is pretty much her takeaway on probiotics overall: They may not do a ton of good, but they won’t really do much harm either). Here are a few ways to get probiotics from food.

    1. Stock up on yogurt.

      Fermented dairy products, like yogurt and kefir, are high in the lactobacillus probiotic.

      “Not all yogurt contains probiotics, so it’s important to read the label and visit the company’s website to look for transparency about this,” says Gorin. (Hint: Look for the National Yogurt Association's “Live & Active Cultures” seal. Chobani and Fage brands are typically safe bets.)

      If you would rather drink your dairy than eat it with a spoon, you can try kefir, a fermented drink made from cow’s or goat’s milk and cultures of yeast and lactic acid bacteria.

      2. Load up on pickled cabbage.

      Like yogurt and kefir, vegetables that are fermented—especially pickled cabbage, like sauerkraut and kimchi—are reliable ways to pump up your probiotic ratio.

      One caveat about pickled cabbage: Most of the products sold in U.S. stores have been through a heating process called pasteurization for safety, which can destroy both good and bad bacteria. So, if you really want to reap the fermentation benefits, look for unpasteurized products or make your own.

      3. Go all in on fermented cheeses.

      So, cheese isn't likely to be first on your list when you think of probiotics, but it turns out fermented cheeses like gouda, cheddar, and Swiss are made with lactic acid bacteria, a probiotic, says nutritionist Jackie Newgent, RD. Quality matters here too (more fermentation equals more probiotics), so make sure the person behind the counter points you to the finest aged gouda there is.

      4. Use apple cider vinegar...on salads.

      Many purported health benefits of ACV are pretty conflated (and are not actually scientifically proven), but ACV really does have probiotics to help your gut health. Instead of taking it via shot (or diluted in water, even), try adding it to your salad dressings for an extra kick of healthy bacteria.

      The bottom line: Probiotics won't work weight-loss magic—but they can help with gut health, so it doesn't hurt to give them a try.