What Are the Most Commonly Used Strains of Probiotics?

Written by: Kari Raman, PharmD, RPh
Published May 29, 2023

There are so many strains of probiotics out there, but what are the most commonly used strains of probiotics and what are their benefits? The most commonly used strains of probiotics in supplements are Saccharomyces, Lactobacillus, and Bifidobacterium. Let’s take a look at each one of the probiotic strains.


Saccharomyces is a type of yeast that consists of several different species that can be used as a probiotic. The most popular and well-known of this genus are Saccharomyces cerevisiae and Saccharomyces boulardii. This yeast is not generally thought of as being one typically found in the human gut, but many probiotic supplements contain S. boulardii because it may possibly have some health advantages in the human GI tract. It has been found that S. boulardii can live through transit within the acidic environment of the stomach and remain alive in the small and large intestine for days after consumption. This yeast however, does not show to stay long-term in the gut, and its effects on gut microbiota function are still under consideration.

Saccharomyces – one of the first recognized probiotics

Saccharomyces boulardii was first found in 1923, by a French scientist Henri Boulard. He was on an expedition in Southeast Asia to study fermentation techniques for food production. During his time in Indochina, he became acquainted with a traditional drink made from the skins of local fruits, lychee and mangosteen. This drink was used in this area to treat diarrhea. 

Boulard was fascinated by this drink to treat diarrhea and started to look into what microorganisms contributed to the medicinal values. He found that a strain of yeast was the leading cause of the digestive therapeutic properties in this drink and he named it Saccharomyces boulardii. 

Boulard’s finding of S. boulardii incredibly innovative at the time because it was when people started to recognize probiotics as therapeutic. This discovery not only revealed the benefits of this particular microorganism, but also brought light to the potential use of traditional therapies. 

What are Saccharomyces probiotics used for?

Saccharomyces are predominantly used to support digestive health. This probiotic has been studied in its use for gastrointestinal conditions. Some possible positive effects of the different Saccharomyces species include that it has been shown to improve gut and digestive health, decreasing inflammation, and possibly help treat diarrhea. This is the most popular species of the Saccharomyces genus of yeasts used in probiotics. Different research studies have shown that Saccharomyces boulardii may help with stimulating the immune system therefore possibly reducing the incidence of infection. It may also be beneficial in reducing symptoms of Irritable Bowel Syndrome, and may help symptoms of eczema.

Other uses of Saccharomyces

  • Saccharomyces cerevisiae, is probably the more well known species of yeast and is known as brewer’s yeast. It is used in brewing and distilling and is often used in the production of beer, wine, and other fermented beverages. It converts sugar into alcohol and carbon dioxide in the fermentation process. 
  • Saccharomyces cerevisiae is also used to bake bread and other baked goods. This yeast is responsible for making baked good rise, it works by producing carbon dioxide in the dough. 
  • Saccharomyces cerevisiae contains vitamins and minerals and is a good source of B vitamins, minerals, and other nutrients in the form of nutritional yeast.
  • Saccharomyces cerevisiae can be used as an ingredient in pet food. Because of its high content of B vitamins, amino acids, and other nutrients, it is thought to support health and wellbeing in dogs and cats and keep their skin and coat healthy. 

Commonly found types of Saccharomyces

There are several types of Saccharomyces, but some of the most commonly found include:

  • Saccharomyces cerevisiae: This is the most well-known and abundantly studied type of Saccharomyces. It is most often used in baking, brewing, and winemaking, and used as a nutritional supplement due to its high content of B vitamins and other nutrients.
  • Saccharomyces boulardii: This strain of Saccharomyces is often used to support gastrointestinal health. It has been studied for its ability to prevent and treat diarrhea and other gastrointestinal conditions. 
  • Saccharomyces pastorianus: This type of Saccharomyces is often used to brew lagers, and is sometimes known as “bottom-fermenting yeast” because of its tendency to settle at the bottom of the container.
  • Saccharomyces uvarum: This strain of Saccharomyces is commonly found in wine and cider, and is sometimes known as “bayanus yeast.”
  • Saccharomyces exiguus: This type of Saccharomyces is commonly found in sourdough bread and other fermented foods. 

Lactobacillus – a common probiotic strain

Lactobacillus is a type of probiotic bacteria that is often found in fermented foods and sometimes added to dietary supplements. Lactobacillus is a type of bacteria that may have potential health benefits for some people. Some doctors and scientific studies have suggested that a few of these possible benefits include improving gut health, boosting the immune system, preventing and treating diarrhea, helping with lactose intolerance, decreasing symptoms of atopic eczema, and potentially helping with weight management. Lactobacillus includes many different species and each one has unique properties. Lactobacillus is naturally found in the digestive tract, like the intestines and colon, and also found in the vagina in women. It is important and helpful for maintaining a healthy balance of bacteria in these areas. A couple of good supplements where you can get L. plantarum are GoodBelly probiotic juice, which has pretty high CFUs per serving, and Good Girl probiotics, which has a solid combination of bacteria – both of which I’ve reviewed.

Like most probiotics, not every particular strain will help every individual. So even though there may be some health benefits for some people, not everyone will find that their particular health issues will improve when this particular probiotic is taken. And always remember, if you are having serious health issues, make sure to see your primary care physician. 

What is the Lactobacillus probiotic used for?

Some potential benefits of Lactobacillus are:

-Possible improvement of digestive and gut health by balancing the gut microbiome and decreasing inflammation.

-May help boost and stimulate the immune system which may help lessen the possibility of infections.

-Preventing and treating diarrhea.

-May assist with lactose tolerance by helping to break down lactose.

-Some studies have shown that certain strains of Lactobacillus can help with decreasing symptoms of atopic eczema.

-Some studies have also shown that Lactobacillus can help with weight management by decreasing body fat and enhancing glucose metabolism. 

-Lactobacillus can help prevent and treat infections in the vagina by controlling the growth of unwanted bacteria and yeast. The proper level of pH balance is important in the vagina  and this bacteria helps maintain the vaginal normal flora. 

What are the most commonly known strains of Lactobacillus?

Lactobacillus includes many different species, some of the most commonly found strains in probiotic products are: Lactobacillus acidophilus, Lactobacillus rhamnosus,  Lactobacillus plantarum, Lactobacillus reuteri, Lactobacillus paracasei, Lactobacillus fermentum, and Lactobacillus casei. Most of these species of Lactobacillus are found in the human gut, in fermented foods, and are used in probiotic supplements to improve gut health and boost the immune system.


Bifidobacterium is a genus of probiotic bacteria that is frequently found in the human gut, in fermented foods, and is often used in probiotic supplements. Some possible benefits of Bifidobacterium are that it may help improve gut health by stabilizing the gut microbiome, decreasing inflammation and enhancing bowel regularity. Bifidobacterium may assist in stimulating the immune system, which could help decrease the risk of infections. Bifidobacterium may possibly help prevent and treat diarrhea and some research suggests that Bifidobacterium may be beneficial in reducing symptoms of Irritable Bowel Syndrome (IBS). Studies have shown that Bifidobacterium may improve the symptoms of atopic eczema and may help with weight management by reducing body fat and improving glucose metabolism. Bifidobacterium additionally may help decrease allergy symptoms by reducing inflammation in the gut.

Some commonly found types of Bifidobacterium include:

Bifidobacterium bifidum: This strain is commonly found in the human gut and is often used as a probiotic supplement.

Bifidobacterium lactis: This strain is found in the human gut and is often used in probiotic supplements to help with digestive issues and boost the immune system.

Bifidobacterium infantis, adolescentis, longum: This species is commonly found in the human gut and is used in probiotic supplements to improve gut health and boost the immune system.

Bifidobacterium animalis, breve: This strain is found in fermented foods and used in probiotic supplements and can improve gut health and boost the immune system. 

You can learn more about probiotic species here. Or read my article on how long it takes for them to work here.

Pharmacist Kari Raman

I’m Kari Raman PharmD, RPh, and I am a licensed, practicing pharmacist. I hold a Doctorate in Pharmacy from The University of the Pacific, and I’ve served patients in retail, compounding and hospital pharmacies.

Probiotics are confusing!

One of the most common questions I get asked by patients is about probiotics. And the truth is, probiotics are not as well understood by the healthcare community as they should be.

So I’ve been reading a lot of probiotic clinical trials, and sharing what I’m learning here.

I hope Pharmacist Probiotics helps you find out if there is a type of probiotic that works for you!