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Bacteria

Bifidobacterium longum

Bifidobacterium longum is a bacterial species that lives naturally in the human gut and is used in probiotic products. Effects can depend on the specific strain.

Gut HealthImmune SupportCognition

What it is studied for

The strongest rated effects first. Bars show the size of the effect, the letter grades the evidence, and each rating lists the studies behind it.

DiarrheaStrongA3 studies
Microbiome healthGut HealthStrongA3 studies
Immune SupportModerateA3 studies
ConstipationModerateA3 studies
InflammationModerateA3 studies
Gut healthModerateA3 studies
All 10 rated effectsGrouped by health goal, with the publications behind each rating

What is Bifidobacterium longum?

B. longum is a bacterial species used in probiotic products. A strain is a more specific identity within the species, and probiotic effects can depend on that strain. The species name alone therefore cannot tell you what a product has been shown to do. 1

How might it affect the gut?

Probiotics can influence gut microbes and their activity, and may temporarily colonize the intestine. The response varies with the person and the strain; a change in microbes is not automatically proof of symptom relief. 1

Key studies

The most recent publications linked to Bifidobacterium longum's ratings.

The gut core microbial species Bifidobacterium longum: Colonization, mechanisms, and health benefits.2024Efficacy of Bifidobacterium longum alone or in multi-strain probiotic formulations during early life and beyond2023Effects of Bifidobacterium longum CLA8013 on bowel movement improvement: a placebo-controlled, randomized, double-blind study2023Usefulness of Bifidobacterium longum BB536 in Elderly Individuals With Chronic Constipation: A Randomized Controlled Trial2022Bifidobacterium Longum: Protection against Inflammatory Bowel Disease2021
All 11 studiesEvery publication linked to Bifidobacterium longum

Why people take it

Gut Health25.5%
Immune Support25.3%
Essential Health22.2%
Detox9.5%
Energy6.7%
Women's Hormones2.2%

SuppCo community snapshot, 2026-09-28. Reasons for use are not evidence that it works.

Questions people ask

Are BB536 and CLA8013 interchangeable?

No. The trials used different preparations and populations, and CLA8013 was heat-killed. Their results need to stay attached to those details. 2 3

Did BB536 cure constipation in older adults?

The trial did not show a significant advantage on its main total constipation score. Stool frequency improved, a more limited result. 2

Can probiotics cause bloating?

Yes. IQWiG lists mild bloating among the occasional adverse effects of probiotics. 4

Is a probiotic the only option for irritable bowel symptoms?

No. IQWiG discusses other approaches, including peppermint oil, selected medicines and psychological treatments. The choice depends on symptoms and individual response. 4

Sources

  1. Probiotics: Fact Sheet for Health Professionals NIH Office of Dietary Supplements