The Number of CFUs The quality of a probiotic supplement has more to do with strains and how many CFUs it provides. (CFU stands for colony forming units, and it refers to the amount of live microorganisms in your supplement.) Although recommendations may vary, Gans says to look for probiotics with at least 1 billion CFUs: “Doses will typically range from 1 billion to 10 billion CFUs for adults; although doses for children are often under 1 billion.”
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.
Probiotics are live bacteria that are present in yogurt, other fermented foods, and in pills. They are promoted as a benefit to the human digestive system. Normally you have trillions upon trillions of bacteria within the colon. Normally we ingest bacteria every time we swallow. Many of these swallowed bacteria may be beneficial while most are simply innocuous and cause no problems. The question for everyone who takes a probiotic much beyond yogurt is whether they really are a health benefit. Here is what we know medically about probiotics.
Here’s a startling fact: For every one human cell we have, there are ten bacteria cells in our body to match it. That means that the majority of DNA in our body isn’t even human; it’s from the 500 bacteria species that call us home.1 Thinking about that much bacteria might have your skin crawling, but the relationship between human and bacteria is really a perfect synergy: we give bacteria room and board, and in return, they work hard to protect our intestinal health, which ultimately protects the health of our immune system and overall well-being. But if we have that much bacteria already living in our gut, you might be thinking to yourself, what are probiotics’ benefits?

The beneficial microbes, including probiotics, live with other microbes that are either benign, pathogenic (disease-causing), or opportunistic, meaning that they normally play nicely but can get out of control if given the opportunity. Actually, any microbe can cause you problems if it ends up in a place other than where it is supposed to be. Such a scenario can happen with intestinal permeability, commonly called leaky gut. Leaky gut happens when the layer of skin-like cells in your GI tract develops gaps in between the cells, allowing food particles, toxins, microbes, and other hazards to enter your bloodstream, if not stopped by the immune system. Since mucus, the thin layer of cells, and your immune system are your only defenses against the outside world within your digestive tract, it is very beneficial to you to have helpful microbes protecting you from potentially pathogenic microbes. These beneficial microbes can produce acids or antimicrobial products called bacteriocins, which hinder or kill pathogens. They can also stand in solidarity to prevent pathogens from taking up residence, or displace them if they do.
*The information and content on this website is provided only for informational purposes. It is not meant in any way as a substitute for the professional advice provided by your physician or any other healthcare professional. The statements on this site have not been evaluated by the FDA. Our products are not intended to diagnose, treat, cure or prevent any disease.

A popular dish in Japan consisting of fermented soybeans, natto contains the extremely powerful probiotic bacillus subtilis, which has been proven to bolster your immune system, support cardiovascular health and enhance digestion of vitamin K2. Natto can also contain vitamin B12, which is usually lacking in vegan diets. It’s also one of the highest plant-based proteins.
Even if some of the bacteria in a probiotic managed to survive and propagate in the intestine, there would likely be far too few of them to dramatically alter the overall composition of one's internal ecosystem. Whereas the human gut contains tens of trillions of bacteria, there are only between 100 million and a few hundred billion bacteria in a typical serving of yogurt or a microbe-filled pill. Last year a team of scientists at the University of Copenhagen published a review of seven randomized, placebo-controlled trials (the most scientifically rigorous types of studies researchers know how to conduct) investigating whether probiotic supplements—including biscuits, milk-based drinks and capsules—change the diversity of bacteria in fecal samples. Only one study—of 34 healthy volunteers—found a statistically significant change, and there was no indication that it provided a clinical benefit. “A probiotic is still just a drop in a bucket,” says Shira Doron, an infectious disease expert at Tufts Medical Center. “The gut always has orders of magnitude more microbes.”
Bottom line: Probiotics are a promising field of research and may one day be used to treat or help prevent many disorders. But there’s not enough solid evidence to recommend their widespread use. Vague claims that probiotics "support good digestive health" are meaningless. Larger, longer and better studies are needed to test specific strains for specific conditions and to determine the proper doses and regimens.
Undaunted, researchers looked into whether probiotics might be beneficial in a host of disorders, even when the connection to gut health and the microbiome was tenuous. Reviews show that there is insufficient evidence to recommend their use to treat or prevent eczema, preterm labor, gestational diabetes, bacterial vaginosis, allergic diseases or urinary tract infections.
Unfortunately, the U.S. has no federal standards for probiotic supplements. Therefore, you run the risk of purchasing a product without any guarantee that it contains its advertised probiotic strains, that the strains are alive, or that the product is free from unhealthy ingredients. Therefore, it may be best to choose a brand-name probiotic that has research backing their effectiveness. Here are some examples:
When it comes to feminine health, the focus is all about balance. Whether you are trying to starve off annoying yeast infections and BV or recurrent urinary tract infections, the secret to optimal health lies in balancing out the bacteria that are already in your system. That’s why these vH Probiotics with Prebiotics and Cranberry contain prebiotic compounds to promote the growth of good bacteria in the digestive and reproductive systems.
What's more, people who have serious heart issues commonly have S. mutans in their heart valves—this is an undesirable type of bacteria that’s actually more often found in the mouth. If your oral microbiome is in balance, S. mutans are normally kept in control by more beneficial species, but if things get out of balance, they can reproduce and make their way into your bloodstream via openings in your gums, compromising your cardiovascular function.3
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. 

Uh, no. “There have been studies that suggest a theoretical link between the microbiome and even changing the microbiome, and changes in the brain,” Lebwohl tells me. He specifically points to this study, in which healthy women with no gastrointestinal issues had their brains imaged before and after a month of consuming yogurt products containing probiotics twice daily.
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!

In the second study, the researchers questioned whether patients should be taking probiotics to counter the effects of antibiotics, as they are often told to do in order to repopulate the gut microbiota after it's cleared by antibiotic treatment. To look at this, 21 volunteers were given a course of antibiotics and then randomly assigned to one of three groups. The first was a "watch-and-wait" group that let their microbiome recover on its own. The second group was administered the same generic probiotics used in the first study. The third group was treated with an autologous fecal microbiome transplant (aFMT) made up of their own bacteria that had been collected before giving them the antibiotic.
A slightly more surprising result, however, seems to be the way that probiotics may impact some of the symptoms of autism. Autism and gut health have been discussed for some time, as patients with the disorder typically suffer from a large number of digestive issues. However, based on animal studies, it seems possible that altering the quality of gut bacteria might benefit not only the digestive system, but the abnormal behaviors in autism, too. In 2016, a case study of a boy with severe autism was reported. While being treated with probiotics for digestive problems, the patient spontaneously improved on the ADOS scale, a diagnostic rating system for people with autism. The score dropped from 20 down three points to a stable 17, and according to the report, ADOS scores do not “fluctuate spontaneously along time” and are “absolutely stable.”
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, chances are any probiotic supplement is going to make some improvement to your digestive health, so don’t be afraid to experiment.
Prebiotics and supplementary ingredients — For probiotic bacteria to grow, they also need prebiotics. High-quality probiotic supplements have both prebiotics and other ingredients designed to support digestion and immunity. Examples of these ingredients are (preferably fermented) flaxseed, chia seed, cañihua seed, astragalus, ashwagandha, hemp seed, pumpkin seed, milk thistle, peas, ginger, mung bean and turmeric.
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."
Probiotics are clearly incredibly supportive, but they can't do their work alone. To make sure that you're getting the most out of your microbes, it's important that you give them the support they need to work. You've got lots of options for supporting your gut health, from dietary changes to probiotic supplementation, but make sure you're at least covering the following bases.
Quick note about some formulations with multiple strains (including this one): Take a look at the label below and you’ll see that the supplement contains a mix of strains, but the label just says there is a total of 20 billion CFUs (how they measure the amount of bacteria). This does not tell us how much of each particular strain there is, and we want to know that there are at least 1 billion CFUs per strain to get a beneficial effect.

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!
If you've ever been to an Indian restaurant, then you've probably seen a lassi—a smoothie made of milk, yogurt, fruit, honey, and cardamom. The drink goes well with spicy Indian food because it helps extinguish the fiery feeling in your mouth. If you want to try it at home, you can pick up bottles from brands like Dahlicious, which contain 15 billion live probiotics per serving and are available in flavors like mango and turmeric. Or, try this mango lassi recipe.
The best probiotic manufacturers will list their potency (in CFUs) at the time of expiration, ensuring 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 bestsellers "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 clearly shows a specific “best by” or “expires on” date on its bottle.
Immunity and colds/flu.There’s a close connection between the bacteria in your colon and the immune system. Several studies, including one in 2012 in the British Journal of Nutrition, have found that certain probiotic strains boost measures of immune response—but whether this translates into any clinical benefits is uncertain. Studies have been inconsistent, for example, as to whether probiotics will actually curb colds and other upper respiratory infections. In 2014 a review in the British Journal of Nutrition, which looked at 20 clinical trials, linked probiotics to shorter duration of colds, but not necessarily reduced incidence or severity. Similarly, a 2015 Cochrane review of 12 clinical trials concluded that certain probiotics may help prevent or shorten such infections, though the quality of the studies was poor.
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.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
As you progress with increasing dosages of probiotics internally, you may experience increased abdominal gas, upset digestion with diarrhea, headache, fever, muscle pain, brain fog, and/or anxiety. If the symptoms become too uncomfortable, decrease the dosage for a few days and try again. These symptoms are your body’s way of telling you that things—such as a die-off of pathogens or an awakened intestinal reflex—are changing.
Further, there’s still a lot we don’t know. A recent study published in Cell compared how the microbiome of the gut reconstituted itself after antibiotic treatment with and without probiotic administration. The researchers found that probiotics (which might have improved diarrhea symptoms) led to a significant delay in microbiome reconstitution, if it occurred at all. And — again — this study was with purified strains of bacteria, which is not what you’re getting in probiotic-containing food.
It is well known that people with lactose intolerance can often consume yogurt with few symptoms. This is because the probiotics in yogurt help digest the lactose in the small intestine, before it reaches the colon. In addition, the yogurt starter cultures L. bulgaricus and Streptococcus thermophilus help to break down the lactose. Because of its probiotics, yogurt is a good way for people with lactose intolerance to consume the recommended servings of dairy without experiencing uncomfortable symptoms they may get from other dairy products.
In the United States, most probiotics are sold as dietary supplements, which do not undergo the testing and approval process that drugs do. Manufacturers are responsible for making sure they're safe before they're marketed and that any claims made on the label are true. But there's no guarantee that the types of bacteria listed on a label are effective for the condition you're taking them for. Health benefits are strain-specific, and not all strains are necessarily useful, so you may want to consult a practitioner familiar with probiotics to discuss your options. As always, let your primary care provider know what you're doing.

Deep Immune Support Probiotics started with a simple premise: Most probiotic strains present on the market today cannot survive the acidic environment of the human digestive system. Additionally, most of the most powerful probiotics require refrigeration, meaning they won’t survive standard delivery services or even room temperatures during your commute or travel.
Probiotic bacteria actually compete against unfriendly flora for bacterial binding sites on the inside lining of your intestines, further protecting you from these harmful pathogens. One way to repopulate your gut with probiotics to restore harmony and get all their many benefits is with the right foods, which can support the growth and proliferation of good bacteria that crowd out the bad ones.
Oral health. An increasing number of probiotic lozenges and gums are promoted for oral health—to reduce periodontal disease, throat infections, and bad breath, for example. There’s preliminary evidence that certain strains may have some benefits, but commercial products may not have the same strains and formulations as those tested in published studies.
Flu is short for influenza, an upper respiratory viral infection. The main problem for you, and the main advantage for the survival of influenza viruses, is that there are many variations that can cause illness. Flu shots are based on virus strains that are anticipated to be widespread. Sometimes those assumptions are correct and other times they are not. This section will show you one overlooked way to fortify your body to best avoid becoming sick with the flu at all, or how to recover if you do succumb.
★50 BILLION 20 STRAINS TARGETED RELEASE FORMULA★NewRhythm 50Billion Probiotics Capsules is Scientifically Backed and Clinically Proven, Formulated by Doctor with 50 Billion Living Organisms Per Serving, Featuring Targeted Release Technology to Help Probiotics Survive Stomach Acids and Reach Your Intestinal Track. Organic Prebiotics Fiber is also Included In the Formula.
Pure Therapeutics Power Probiotic 100B offers 100 billion CFUs of 4 powerful probiotic strains, including science darling, the HN019 strain of Bifidobacterium lactis. Since environmental factors, including moisture, oxygen and heat, can degrade the stability of your probiotics, Pure Therapeutics 100B is delivered in nitrogen-purged aluminum blister pacts, which ensure viability until the probiotic hits your system. No refrigeration is required.
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