Although some probiotics have shown promise in research studies, strong scientific evidence to support specific uses of probiotics for most health conditions is lacking. The U.S. Food and Drug Administration (FDA) has not approved any probiotics for preventing or treating any health problem. Some experts have cautioned that the rapid growth in marketing and use of probiotics may have outpaced scientific research for many of their proposed uses and benefits.


As the best-selling author of Happy Gut and a medical doctor who specializes in gut health and once suffered from IBS (irritable bowel syndrome), I have experienced for myself, as well as see on a daily basis, how a disrupted gut flora opens the door for unfriendly microbes to step in and take over, creating all sorts of pandemonium that causes patients to gain weight, feel sick and tired, and become more disease-prone.
Until recently, testing of probiotics by ConsumerLab.com found that some products had far lower amounts of live organisms than claimed on the labels. But in 2018, it found that 17 out of 18 products tested contained the amounts listed; none exceeded limits for heavy metal contaminants. In contrast, in 2016, a study in Pediatric Research found that only one out of 16 Bifidobacterium longum supplements tested contained the species named on the label.

Rachel Allen is a writer at Hyperbiotics who's absolutely obsessed with learning about how our bodies work. She's fascinated by the latest research on bacteria and the role they play in health, and loves to help others learn about how probiotics can help the body get back in balance. For more ideas on how you can benefit from the power of probiotics and live healthier days, be sure to subscribe to our newsletter. To learn more about how a healthy microbiome can enrich your life, subscribe to our newsletter.
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 ingredient lists to find the supplements containing the highest number of effective strains for each use case.
The latest two-part research on probiotics was spearheaded by researchers at the Elinav Lab of Immunology at the Weizmann Institute of Science in Israel and colleagues at the Tel Aviv Medical Center. Eran Elinav served as a senior author for both studies along with Eran Segal and his lab of computational biologists who focus on health and disease related to microbiome, nutrition, genetics, and gene regulation. 
Most probiotics designed for women are designed to target feminine health conditions like yeast infections and urinary tract infections OR overall digestive health. While this may not be a concern for some women, the fact is that most of us can benefit from probiotics that keep our reproductive systems in check while also promoting overall digestive and immune health. That’s why we love the Culturelle Women’s Healthy Balance Probiotic: this women’s probiotic was specially designed to maintain feminine health without sacrificing the digestive and immune support of traditional probiotics!
Scientists are investigating probiotics, and their combined effects, by trying to classify the probiotic benefits of ingesting specific probiotic strains and understanding their role in the digestive tract. At present, the methodological and ethical limitations of human studies still make it difficult to fully understand the mechanisms of action of probiotics, but some explanations are available. Nevertheless, benefits linked to the consumption of probiotic strains have already been suggested (e.g. helping to support the immune system, help support digestive health), and others are still being investigated.
There’s good and bad bacteria in there (fascinating fact: an estimated 100 trillion bacteria live inside your digestive tract): When the good outweighs the bad, your immune health soars; when the bad overpowers good, you get sick. You have diarrhea. Your immune system tanks. Your IBS, lactose intolerance, and other gut problems are exacerbated. It throws your entire system out of whack.
I didn’t know there was much of a difference between probiotics until I did some research. After realizing the ones I had been getting were probably not doing anything for me, I wanted to invest in a better option. This brand checked all the boxes and was still really affordable! I’ve been taking them for about a week now and I can tell a difference! The first few days I didn’t feel too great but realized it was because this probiotic was actually doing something for me and rebalancing my gut. Now I feel less bloated and all around healthier. I will definitely be getting more!
Dr. Michelle Schoffro Cook says 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:
On my recent trip to Japan, one thing I noticed was the inclusion of pickled vegetables in almost every traditional Japanese meal. Unfortunately, many Americans don’t consume enough of these probiotic-rich foods and drinks. Even when they do, restoring equilibrium oftentimes requires therapeutic doses of these microorganisms, because most everyone has been on several rounds of antimicrobials. That’s where a probiotic supplement comes in.
The probiotic industry is booming, but the benefits of probiotic products and the quantity of viable bacteria they contain can vary. So, instead of adding bacteria from an outside source, you might be better off consuming prebiotics, like fermentable fiber, which support your own beneficial bacteria, Dr. Cresci says. Good dietary sources of prebiotics include dried beans and other legumes, garlic, asparagus, onions, leeks, certain artichokes, green bananas and wheat. Prebiotic supplements are available, as well.
"Many chronic health problems and inflammatory diseases are caused by a damaged microbiome where the good bacteria is overrun by the harmful bacteria and can't reinforce the gut walls, which results in increased intestinal permeability where bacteria and toxins leak through the intestines into the bloodstream triggering a system-wide immune response of inflammation that is a part of our body's natural healing cycle."
Back to the question of what are probiotics: There are five main types, each in its own classification called a genus. Within each genus there are multiple species, and within those species there are multiple strains. For example, Lactobacillus is a very common genus of probiotics. Within that genus are numerous species, such as rhamnosus. The genus and species of a microbe are always italicized, making it easy to know that a microbe is involved. In a species such as Lactobacillus rhamnosus (often abbreviated L. rhamnosus), there are many strains. An example of the name of a strain is L. rhamnosus GR-1.
A number of probiotic products are on the market, including yogurts containing probiotics, as well as supplements and skin creams, and an estimated 3.9 million Americans use such products. Some studies suggest that probiotics may help with diarrhea or symptoms of irritable bowel syndrome (IBS), but strong evidence to support their use for most health conditions is lacking, according to the National Center for Complementary and Integrative Health.
Myriad factors – antibiotics, diet, stress, and age, among them – affect the balance of diverse microbes present in your gut. While you can replenish your gut bacteria by eating well and incorporating natural probiotics (ex. yogurt and kefir) into a healthy diet, these processes can take weeks or months; taking a regular probiotic is an easy and effective way to ensure your gut (and immune system) stays healthy, always.
The science on what probiotics do is still emerging. There is some hard evidence that suggests eating probiotic foods and supplements can have a beneficial effect on health. Other evidence suggests probiotics benefits are limited to those individuals in good health and should be avoided by those who suffer from certain serious health conditions. There is no research that demonstrates the risks or the benefits of probiotic supplements on children.
Keep in mind that when supplements contain a specific number of organisms, this number may not be what is actually within each capsule at the time of purchase. Probiotics are living organisms and can die out easily. Especially if that supplement sits on your drugstore or warehouse shelf for months or longer, the number of organisms you get may be far less than what the bottle claims. Hardier strains have a longer shelf life. Capsule strength decays faster if the probiotic has been sitting around at elevated temperatures during transport to the store. Companies actually have to produce probiotics with a much higher CFU (colony-forming units; see below) count in each capsule in order to guarantee the label potency by the expiration date.
Do you strain with infrequent bowel movements? Do the feces look like separate hard lumps or like bunches of hard lumps stuck together, or are they pencil-thin? You may have constipation. The Bristol stool chart (BSC) was developed by two doctors as a way to differentiate between states of constipation, normal elimination, a state of lacking fiber, and states of inflammation. Stools are supposed to be long and sausage-like, with few or no cracks in the surface.
Then, study participants were divided into one group that consumed a standard probiotic strain available in commercial supplements and a control group that was given a placebo. After two months of treatment, the researchers found that some people were so-called “resisters” who expelled the gut microbiomes in probiotics; others were identified as “persisters” who successfully colonized the generic probiotic strains in their GI tracts.
​​​​​​AZO Complete Feminine BalanceTM is a daily probiotic supplement designed for the unique needs of women. Many everyday things can throw off your balance (stress, sex, pregnancy, aging, even medications! This product supports your feminine health and maintain a healthy pH so that you can own your day! It contains INTELLIFLORATM: a probiotic blend of four lactobacilli that are associated with vaginal health* (Lactobacillus crispatus LBV 88, Lactobacillus rhamnosus LBV 96, Lactobacillus jensenii LBV 116, and Lactobacillus gasseri LBV 150.)  The INTELLIFLORATM blend has been shown in clinical studies to help restore and maintain the healthy balance of the vaginal microbiota.*
A 2017 survey of cancer patients showed that more than 80 percent were taking some sort of dietary supplement, vitamin, mineral, or herb to treat digestive issues they were experiencing due to chemotherapy. Researchers noted that while supplements can be beneficial in some cases, they can also change the metabolism of anti-cancer drugs, or lead to life-threatening conditions like sepsis because of the patient’s compromised immune system.
“Microbiome” refers to the trillions of bacteria and microorganisms that live on and in our individual bodies. “There’s increased recognition of the various ways that the microbiome affects our health,” Lebwohl tells me. “And with that recognition comes the true observation that many bacteria are good for us. This goes against the old idea that bacteria equal germs, which equal harm. It turns out that many bacteria keep us healthy and probiotics could potentially support that notion.”
Probiotics produce enzymes that help break down chemicals 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.
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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 the new study, the researchers analyzed information from 15 healthy volunteers who took either a probiotic product containing 11 strains of bacteria, or a placebo, for four weeks. The participants also underwent colonoscopies and upper endoscopies before they took the probiotics or the placebo, and again after the four-week treatment period. (An upper endoscopy looks at the upper part of the digestive tract.) During these procedures, the researchers took samples from inside participants' guts.


There is one Voluntary Certification Program by which a supplement manufacturer can choose to be evaluated. ConsumerLab.com (CL) is the leading provider of independent test results and information to help consumers and health-care professionals identify the best quality health and nutrition products. Products that have passed their testing for identity, strength, purity, and disintegration can print the CL Seal of Approval on their product. This is one step toward being confident that one is getting the amount and type of probiotic promised by the manufacturer.

The other way that probiotics help is the impact that they have on our immune system. Some believe that this role is the most important. Our immune system is our protection against germs. When it doesn't function properly, we can suffer from allergic reactions, autoimmune disorders (for example, ulcerative colitis, Crohn's disease, and rheumatoid arthritis), and infections (for example, infectious diarrhea, H. pylori, skin infections, and vaginal infections). By maintaining the correct balance from birth, the hope would be to prevent these ailments. Our immune system can benefit anytime that balanced is restored, so it's never too late.
Do you strain with infrequent bowel movements? Do the feces look like separate hard lumps or like bunches of hard lumps stuck together, or are they pencil-thin? You may have constipation. The Bristol stool chart (BSC) was developed by two doctors as a way to differentiate between states of constipation, normal elimination, a state of lacking fiber, and states of inflammation. Stools are supposed to be long and sausage-like, with few or no cracks in the surface.
Uncontrolled changes in blood sugar levels or a decreased ability to regulate insulin can have serious effects on your overall health, and since far more men than women are at risk for these changes, these issues are well worth paying attention to.5 Research indicates that regularly taking probiotic supplements containing Lactobacillus and Bifidobacterium can help your body maintain blood sugar levels already within a normal range, whether you're simply at risk for insulin-related challenges or you're already experiencing them.
Jigsaw Essential Blend Probiotics uses five of the most researched (and effective) live strains to promote a healthy digestive system, restore flora after antibiotics use, and help with optimal vitamin absorption. Jigsaw products are also third-party certified, so you can rest assured that each batch is safe and pure. The bottom line? If you’re looking for a vegan-friendly formula — the capsules are made from HPMC (Hypromellose - Hydroxypropyl Methylcellulose), gelling agent (Gellan gum), and water — with a high CFU count, this product is for you. There are 90 capsules per bottle.

They can break down substances in foods that keep you from absorbing the micronutrients inside. They not only protect against the consequences of rogue molecules passing through a leaky gut, but they assist your intestinal cells in staying healthy to optimize nutrient absorption. In addition, some of the metabolic by-products of probiotics, such as short-chain fatty acids and vitamin production, are very nourishing to your GI tract.
The scientists discovered that the probiotics successfully colonized the GI tracts of some people, called the "persisters," while the gut microbiomes of "resisters" expelled them. Moreover, the persister and resister patterns would determine whether probiotics, in a given person, would impact their indigenous microbiome and human gene expression. The researchers could predict whether a person would be a persister or resister just by examining their baseline microbiome and gut gene expression profile. 

Probiotics are found in everything from chocolate and pickles to hand lotion and baby formula, and millions of people buy probiotic supplements to boost digestive health. But new research suggests they might not be as effective as we think. Through a series of experiments looking inside the human gut, researchers show that many people's digestive tracts prevent standard probiotics from successfully colonizing them. Furthermore, taking probiotics to counterbalance antibiotics could delay the return of normal gut bacteria and gut gene expression to their naïve state. The research publishes as two back-to-back papers on September 6 in the journal Cell.
In addition to the impact on our immune systems, our digestive systems are the second largest part of the neurological system. It’s called the enteric nervous system and is located in the gut. This is why it’s called the second brain — the gut is responsible for creating 95 percent of the serotonin and may have significant impact on brain function and mood.

According to a 2014 meta-analysis, probiotics benefit diabetics by improving insulin sensitivity and decreasing the autoimmune response found in diabetes. The authors suggest that the results were significant enough to conduct large, randomized, controlled trials (the “gold standard” of scientific studies) to find if probiotics may actually be used to prevent or manage diabetes symptoms. Combining probiotics with prebiotics may also help manage blood sugar, particularly when blood sugar levels are already elevated. (87)

As you age, your body needs different supplements and vitamins to stay healthy. Renew Life 50+ Ultimate Flora Probiotic is a smart choice for adults over 50 because it is specifically formulated with seniors in mind. It has 30 billion live cultures and 12 strains of probiotics, including Bifidobacteria, which is a probiotic that decreases in your body as you age. Seniors develop less of the “good” bacteria as they age, and Ultimate Flora has three times the average live cultures in each dose to help replenish and protect gut and immune health. This 60-day supply should be refrigerated to maintain the live cultures.
Some studies suggest that certain probiotic strains may also help in mild to moderate ulcerative colitis and possibly for bloating and gas in irritable bowel syndrome (IBS). Probiotic supplements, on the whole, “improve global symptoms, bloating, and flatulence in IBS,” by modifying the gut microbiome, according to a 2014 monograph from the American College of Gastroenterology. As IBS researchers said in a paper in Gastroenterology & Hepatology in 2015, “The concept of manipulating the microbiome is one of the most promising new ways in which to treat patients with IBS, but there is still much to learn.”
Walk into any grocery store, and you will likely find more than a few “probiotic” products brimming with so-called beneficial bacteria that are supposed to treat everything from constipation to obesity to depression. In addition to foods traditionally prepared with live bacterial cultures (such as yogurt and other fermented dairy products), consumers can now purchase probiotic capsules and pills, fruit juices, cereals, sausages, cookies, candy, granola bars and pet food. Indeed, the popularity of probiotics has grown so much in recent years that manufacturers have even added the microorganisms to cosmetics and mattresses.
You experience that afternoon slump and reach for a candy bar or a sugar-laden coffee. Or maybe you go through your day, starting with a breakfast of doughnuts or sugary cereal, and then proceed to sodas for drinks, cookies to snack on, dessert after dinner, and finally to a nighttime snack of ice cream. You know that feeling; it’s that I-have-to-have-something-sweet-and- I-have-to-have-it-NOW feeling.

The large intestine is home to hundreds of trillions of bacteria. Fortunately, most are neutral or even beneficial, performing many vital body functions. For example, they help keep “bad” bacteria at bay, play a role in immunity, help us digest food and absorb nutrients and may even have anticancer effects. But will consuming them as probiotics in foods or capsules make a notable difference to your health—especially if you are already healthy? Here’s a look at the evidence.
Did you know that bacteria might actually keep you healthy? It all just depends on the type of bacteria. In this case, we’re talking about the benefits of probiotics. Probiotics benefits are some of the most widely researched natural solutions to gut health. For years, scientists and physicians have observed the many benefits of probiotics for not just the gut, but for the entire body.
As with other types of supplements, scientists are still discovering the full potential of probiotics. However, when taken regularly, it is believed that they help support digestive health by helping maintain the balance of beneficial and non-beneficial bacteria in your digestive tract. Having a natural balance of good bacteria in the digestive tract can help defend against occasional digestive issues. In addition, probiotics play an important role in supporting immune health, since 70% of the body's immune system is found in the digestive tract.∗
In the 2016 paper, Dr. Ghannoum and is research partners looked at parameters of microbiome makeup in Crohn’s Disease patients and healthy members of the same families in an area in Belgium.  The researchers said they “​identified positive interkingdom correlations between C.​ ​tropicalis​ (a fungus), E.​ ​coli, and S.​ ​marcescens​ (both microbial species) ​in CD patients and validated these correlations using in vitro biofilms​. These results provide insight into the roles of bacteria and fungi in CD.​”​
Evidence from clinical trials is mixed and often of low quality, but findings from meta-analyses suggest that probiotics can provide benefits in the treatment of some conditions, such as infectious and antibiotic-associated diarrhoea. As such, taking probiotics after antibiotic treatment is an increasingly common practice. However, two studies recently reported in Cell question whether taking highly concentrated supplements of so-called good bacteria aids the recovery of normal gut flora.

Even for those without an urgent problem, probiotics can help with overall digestive management. Challa argues in his book, Probiotics For Dummies, that good bacteria help "crowd out" bad bacteria. That's because the intestine is lined with adherence sites where bacteria latches on. If the sites are populated with good-for-you microbes, there's no place for a harmful bacterium to latch on.

Having a healthy gut flora means an abundance for your health, digestion, wellbeing and even beauty! As we saw last week, there is ongoing communication between your GI and your brain known as the gut brain axis. This means a healthy gut can benefit the regularity of your digestion as well as cognitive function like mood and depression, and even the health and appearance of your skin.


According to a 2014 meta-analysis, probiotics benefit diabetics by improving insulin sensitivity and decreasing the autoimmune response found in diabetes. The authors suggest that the results were significant enough to conduct large, randomized, controlled trials (the “gold standard” of scientific studies) to find if probiotics may actually be used to prevent or manage diabetes symptoms. Combining probiotics with prebiotics may also help manage blood sugar, particularly when blood sugar levels are already elevated. (87)
"Contrary to the current dogma that probiotics are harmless and benefit everyone, these results reveal a new potential adverse side effect of probiotic use with antibiotics that might even bring long-term consequences," Elinav said in a statement. "In contrast, replenishing the gut with one's own microbes is a personalized mother-nature-designed treatment that led to a full reversal of the antibiotics' effects." Segal added, "This opens the door to diagnostics that would take us from an empiric universal consumption of probiotics, which appears useless in many cases, to one that is tailored to the individual and can be prescribed to different individuals based on their baseline features."
Notably, after someone was tagged a “persister” or “resister” clear patterns emerged on how probiotics would impact his or her indigenous microbiome and gut bacteria profile. "Although all of our probiotic-consuming volunteers showed probiotics in their stool, only some of them showed them in their gut, which is where they need to be," Eran Segal said in a statement. "If some people resist and only some people permit them, the benefits of the standard probiotics we all take can't be as universal as we once thought. These results highlight the role of the gut microbiome in driving very specific clinical differences between people."
To avoid those and other problems, I strongly recommend buying a professional brand from a reputable health care professional or other vendor who stands by their products and undergoes third-party testing. Some of these professional brands have created advanced technology that preserves a probiotic supplement’s survival on the shelf and in your gut.
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