What Is Lactobacillus Gasseri?

Probiotic strain offers specific digestive and vaginal properties

Lactobacillus Gasseri tablets and capsules

Verywell / Anastasia Tretiak

Lactobacillus gasseri is a strain of Lactobacillus, a genus of bacteria naturally found in the digestive and urinary tracts. The bacteria are thought to help the body by suppressing harmful bacteria. This process, in turn, may enhance immune function and aid digestion.

Lactobacillus gasseri is but one of several different types of probiotic bacteria, which also include:

This article reviews the uses of Lactobacillus gasseri, its potential side effects, and what to look for in probiotic supplements.

Dietary supplements are not regulated like drugs in the United States, meaning the Food and Drug Administration (FDA) does not approve them for safety and effectiveness before products are marketed. When possible, choose a supplement that has been tested by a trusted third party, such as USPm ConsumerLabs, or NSF.

However, even if supplements are third-party tested, that doesn't mean they are necessarily safe for all or effective in general. Therefore, it is important to talk to your healthcare provider about any supplements you plan to take and to check in about any potential interactions with other supplements or medications.

Supplement Facts

  • Active ingredient(s): Lactobacillus gasseri
  • Alternate name(s): L. gasseri
  • Suggested dose: No standard dose established
  • Safety considerations: Avoid if pregnant, breastfeeding, or immunocompromised. Speak to a pediatrician for appropriate dosing in children.

Researched Uses of Lactobacillus Gasseri

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease.

Probiotics are generally regarded as beneficial to digestive health.

For its part, Lactobacillus gasseri is marketed as offering specific health benefits on its own or in combination with other probiotic bacteria. These suggested benefits include the prevention of bacterial vaginosis (inflammation of the vagina) and peptic ulcers (sores on the lining of the stomach).

It has also been suggested to help control ulcerative colitis (inflammatory bowel disease, or IBD, causing ulcers in your digestive system), irritable bowel syndrome (IBS, which affects the large intestine), and endometrial (pelvic) pain.

However, the research to date is mixed, with studies looking at multiple strains of probiotics at different doses and outcomes. There is not a lot of research on Lactobacillus gasseri alone. However, some have looked at its effects on weight loss.

Overall, there is insufficient evidence to support recommending Lactobacillus gasseri for weight loss, vaginal health, or conditions affecting the small and large intestines.

Research on Weight Loss

There is no such thing as a "miracle supplement" for weight loss. Despite some research on the matter, there is not enough evidence to support that Lactobacillus gasseri has a direct effect on body fat or weight loss.

If you are concerned about your weight, consult a healthcare provider for medical advice on the proper steps to improving your health. Behavioral lifestyle interventions, such as healthy eating and physical activity, remain an integral part of any weight management plan.

A few clinical trials have examined the effect of Lactobacillus gasseri on abdominal fat and weight loss:

  • One study included 210 adults with obesity who were given either milk enriched with Lactobacillus gasseri or a placebo milk (plain milk). After 12 weeks, the Lactobacillus group experienced an 8.5% reduction in abdominal fat compared to the placebo group.
  • Another clinical trial evaluating Lactobacillus gasseri versus placebo found that the Lactobacillus gasseri reduced visceral fat mass in adults with obesity.

The same conclusions have not been reached in other studies:

  • One study of 62 adults with obesity given a 12-week course of Lactobacillus gasseri showed no significant weight changes compared with adults given a placebo.
  • A systematic review of trials comparing a Lactobacillus species to placebo for weight loss found conflicting results. Of the 14 trials studied, nine showed weight loss, two showed weight gain, and three showed no effect. The authors believe the various results may have been due to different probiotic species used during the study.

More research is needed to determine the exact role Lactobacillus gasseri plays in abdominal fat and weight loss.

What Are the Side Effects of Lactobacillus Gasseri?

Probiotics like Lactobacillus gasseri are generally considered safe with few short-term or long-term side effects.

In some cases, Lactobacillus gasseri may trigger gas and bloating. Most cases are mild and tend to improve as your body adapts to the supplement.

Lactobacillus Gasseri tablets
Verywell / Anastasia Tretiak


The use of Lactobacillus during pregnancy or breastfeeding has been under-researched. While it is generally considered safe, speak with your ob-gyn to fully understand the benefits and risks, including whether you need a probiotic.

Some probiotics may contain traces of milk proteins, so people with milk allergies should be cautious using probiotics or avoid them.

Probiotics are generally not recommended for people with compromised immune systems. These include people with advanced human immunodeficiency virus (HIV) infection, organ transplant recipients, and others taking immunosuppressive drugs for cancer and other conditions.

Without an intact immune system, it is possible that probiotic bacteria can overgrow. In rare cases, Lactobacillus can cause an infection in the chambers of the heart and heart valves.

If you have a weakened immune system or are taking immunosuppressive medications like prednisone, Otrexup (methotrexate), or Sandimmune (cyclosporine), speak with your healthcare provider before taking a probiotic supplement.

Dosage: How Much Lactobacillus Gasseri Should I Take?

Lactobacillus gasseri supplements are available in many grocery stores, drugstores, and health food stores, either as a single supplement or as part of a combination probiotic.

The strength of Lactobacillus products is indicated by the number of living organisms per capsule or tablet, also known as colony forming units (CFU). Generally speaking, many probiotic products contain 1 to 10 billion colony forming units per dose.

There is no established recommended dose for Lactobacillus gasseri.

What Happens If I Take Too Much Lactobacillus Gasseri?

There is not a lot of data on what could happen if taking too much of a probiotic. Always follow the instructions on the product label for dosing. Never take more than recommended.


Antibiotics may reduce the effectiveness of probiotics if taken at the same time, so it is suggested to take probiotics two hours apart from your antibiotic dose.

It is essential to carefully read the ingredient list and nutrition facts panel of a supplement to know which ingredients and how much of each ingredient is included. Please review this supplement label with your healthcare provider to discuss any potential interactions with foods, other supplements, and medications.

How to Store Lactobacillus Gasseri

In general, probiotics should be stored in a cool and dark place. Some products suggest storing it in the refrigerator. Be sure to read the directions for storage for each product. Always store medications and supplements out of reach of children and pets to prevent accidental consumption.

Frequently Asked Questions

  • Is Lactobacillus gasseri a good probiotic to take?

    Lactobacillus gasseri is a strain of Lactobacillus, a beneficial bacteria in the digestive and urinary tracts. There are several different strains of probiotics, and research has shown the different strains may have different effects. However, there is not enough evidence to recommend it for purported uses, such as weight loss.

  • Should everyone take probiotics?

    No. If you haven't any problems with your digestive health, you more than likely are getting all the probiotic bacteria you need from food. Additionally, there is insufficient data to support recommending probiotics for pregnant or breastfeeding people. People with compromised immune systems also should avoid probiotics.

  • Is Lactobacillus gasseri recommended for vaginal health?

    Most of the studies on bacterial vaginosis were multi-strain products, so it is difficult to say whether L. gasseri alone will help.

    For example, a clinical trial involving a yogurt product with multiple probiotic strains found that it led to improved recovery rates and symptoms in patients with bacterial vaginosis.

    On the other hand, L. gasseri may help lessen menstrual pain in women with endometriosis (tissue normally lining the uterus that grows outside the organ). This was reported in a small study published in the journal Cytotechnology in 2011.

  • Should Lactobacillus gasseri be used to prevent or treat H. pylori?

    We don't know the answer to this yet. A review of studies published in PLoS One evaluated the effects of probiotic supplements in eliminating Helicobacter pylori (H. pylori), a bacterium known to be the main cause of stomach ulcers. While probiotics in general may help alleviate H. pylori, it is not known how much more or less effective Lactobacillus gasseri alone would be.

Sources of Lactobacillus Gasseri & What to Look For

Probiotics can be found in foods and supplements. Probiotics are in fermented foods like yogurt. In foods, look for probiotics "added" rather than "used during making," which means the probiotics used while making foods are killed when heated.

Supplements can be in tablets, capsules, powders, and more. Lactobacillus gasseri is mostly available as capsules and in combination with other probiotic strains.

The FDA classifies probiotics like Lactobacillus gasseri as dietary supplements. Under this classification, they neither require clinical research nor quality testing to reach store shelves. Because of this, the quality can vary from one brand to the next, sometimes considerably.

To ensure quality and safety, only choose brands tested and certified by an independent certifying body like the U.S. Pharmacopeia (USP), ConsumerLab, or NSF International.

Any probiotic product should be labeled with the type of bacteria or yeast it contains and its quantity. Names of the organisms are usually listed in italic type, and the first word is captalized. For example, Lactobacillus acidophilus or L. acidophilus.

Products may contain one type of probiotic or several different strains combined. Products should be chosen based on the efficacy of that particular strain for a given condition. In general, there is not enough data to support taking products that combine multiple different strains.

The quantity of live organisms should be listed and state the quantity at the end of its shelf life, not at the time of manufacturing. Quantities are listed in cell amounts or colony forming units (CFU). Active ingredients in probiotic supplements can decrease over time so avoid using products beyond the expiration date.

It is also important to look for probiotics that can hold up in the acidic environment of the stomach. Some tablet forms are enteric coated for this reason. Most Lactobacillus, Bifidobacterium and Streptococcus probiotics can survive the environment of the stomach.


Probiotic supplements are extremely popular and marketed for several conditions but mostly for bowel disease and digestive health. Probiotics are live organisms, and there are several different strains used in supplements. Lactobacillus gasseri is one type of probiotic. This strain has shown some promise as a complementary aid in weight loss, but further research is needed.

Lactobacillus gasseri has been studied for its role in weight loss, vaginal health, and endometriosis pain. Currently, there is not enough evidence to recommend Lactobacillus gasseri for any of these uses. Talk to your healthcare provider or pharmacist before starting any probiotic supplement to determine if it's the right choice for you.

16 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Jennifer Lefton, MS, RD/N, CNSC, FAND
Jennifer Lefton, MS, RD/N-AP, CNSC, FAND is a Registered Dietitian/Nutritionist and writer with over 20 years of experience in clinical nutrition. Her experience ranges from counseling cardiac rehabilitation clients to managing the nutrition needs of complex surgical patients.

Originally written by Cathy Wong
Cathy Wong

Cathy Wong is a nutritionist and wellness expert. Her work is regularly featured in media such as First For Women, Woman's World, and Natural Health.

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