Background

Limosilactobacillus fermentum (L. fermentum) is a type of probiotic ("good" bacteria) found naturally in the human body. It's also found in fermented foods.

"Good" bacteria such as L. fermentum might help the body break down food, absorb nutrients, and fight off "bad" organisms that might cause diseases. These bacteria are sometimes added to fermented foods like yogurt and also found in dietary supplements.

People use L. fermentum for asthma, eczema, colic, flu, obesity, and many other conditions, but there is no good scientific evidence to support these uses.

Don't confuse L. fermentum with other probiotics, or with fermented food products such as fermented milk, kefir, or yogurt. These are not the same. Also note that L. fermentum used to be classified under the Lactobacillus genus. But Lactobacillus was split up into 25 different genera in April 2020. Some product labels might still list this species as Lactobacillus fermentum rather than its new name, Limosilactobacillus fermentum.

Safety Safety definitions

When taken by mouth: L. fermentum is possibly safe when used alone or together with other probiotics for up to 12 weeks. It seems to be well-tolerated. Some people might experience mild stomach side effects.

When applied to the vagina: L. fermentum is possibly safe when used daily for up to 7 days and biweekly and/or monthly for up to 10 weeks.

Special Precautions & Warnings:

Pregnancy: There isn't enough reliable information to know if L. fermentum is safe to use during pregnancy. But there's no reason to expect safety concerns when used appropriately.

Breast-feeding: L. fermentum is possibly safe when taken by mouth while breast-feeding. It's been used safely for up to 16 weeks.

Children: L. fermentum is possibly safe for children of most ages when taken by mouth. It's been used safely alone or together with other probiotics for up to 6 months. But there isn't enough reliable information to know if L. fermentum is safe for very small premature infants.

Weakened immune system: Probiotics have caused blood infections in a small number of people with weakened immune systems. If you have a weakened immune system, talk with your healthcare provider before taking probiotics, including L. fermentum.

Damaged heart valves: Probiotic preparations can cause an infection in the inner lining of the heart chambers and heart valve. This is extremely rare, but people with damaged heart valves should stop taking probiotics, including L. fermentum, before dental procedures or surgical procedures.

Effectiveness

Dosing & administration

L. fermentum has most often been used by adults alone or together with other probiotics in doses of 1-3 billion colony-forming units by mouth daily for up to 4 weeks. It's also been applied to the vagina in a suppository or tablet. In children, doses have varied. Speak with a healthcare provider to find out what type of product and dose might be best for a specific condition.

Interactions with pharmaceuticals

Antibiotic drugs

Interaction Rating=Moderate Be cautious with this combination.

L. fermentum is a type of friendly bacteria. Antibiotics are used to reduce harmful bacteria in the body. Taking antibiotics along with L. salivarius can reduce the effects of L. fermentum. To avoid this interaction, take L. fermentum products at least 2 hours before or after antibiotics.

Interactions with herbs & supplements

There are no known interactions with herbs and supplements.

Interactions with foods

There are no known interactions with foods.