Skip to content
Gut Metabolic
Gut Metabolic
Explore probiotic rankings

Probiotic strain · 12 human trials behind this page

Lactobacillus rhamnosus GG (LGG): what the human trials show

Lacticaseibacillus rhamnosus GG (formerly Lactobacillus rhamnosus GG)

LGG is one of the most-studied probiotic strains. Pooled trials show it lowers the chance of diarrhea during antibiotics, clearly in children; in adults the overall result was not significant, apart from people on H. pylori treatment.

The studies, one by one

  1. 2015Meta-analysis of 12 randomized trialsPartly favored

    1,499 children and adults taking antibiotics

    Antibiotic-associated diarrhea fell from 22.4% to 12.3% with LGG overall. Split by age, the benefit was significant in children (5 trials) but not in adults (6 trials), except in adults taking antibiotics to clear H. pylori (4 trials). The authors rated the evidence moderate to low quality.

    Szajewska H, Kołodziej M Systematic review with meta-analysis: Lactobacillus rhamnosus GG in the prevention of antibiotic-associated diarrhoea in children and adults. Alimentary Pharmacology & Therapeutics, 2015. PubMed 26365389

  2. 2012Meta-analysis of 63 randomized trials (all probiotic types, mostly Lactobacillus-based)Favored the strain

    11,811 people taking antibiotics

    Probiotics as a group lowered antibiotic-associated diarrhea by about 42%. Most trials used Lactobacillus products, but strains were often poorly documented, so the result supports the category more than LGG alone.

    Hempel S, Newberry SJ, Maher AR, et al. Probiotics for the prevention and treatment of antibiotic-associated diarrhea: a systematic review and meta-analysis. JAMA, 2012. PubMed 22570464

What the evidence doesn't show

  • The clear benefit is in children; the adult result was not significant overall.
  • The evidence quality was rated moderate to low.
  • LGG has no weight or blood-sugar data in the trials cited here; the L. rhamnosus strain studied for weight is a different one (CGMCC1.3724).

How to find it on a label

LGG is one strain of L. rhamnosus. The species is now classed in the genus Lacticaseibacillus, so newer labels may use that name. Other L. rhamnosus strains, such as CGMCC1.3724 (studied for weight in women), are different strains with different evidence, so look for "GG" on the label.

Names you may see: LGG · L. rhamnosus GG · Lactobacillus rhamnosus GG · Lacticaseibacillus rhamnosus GG

Is it in anything we rank?

Yes: Ritual Synbiotic+ lists this exact strain. See how it compares on our metabolic probiotic ranking.

Related reading

Questions

Does LGG prevent diarrhea from antibiotics?

In children, yes: across five trials the risk roughly halved. In adults the pooled result was not statistically significant, except for people taking antibiotics for H. pylori. The evidence was rated moderate to low quality.

Does LGG help with weight loss?

Not on the evidence here. The L. rhamnosus strain with weight data is CGMCC1.3724, a different strain. A product with LGG carries none of that strain's results.

Which products contain LGG?

On our metabolic probiotic ranking, Ritual Synbiotic+ lists LGG alongside BB-12. LGG is also sold on its own. Whatever you buy, check that the label prints "GG" and not just "L. rhamnosus", since other rhamnosus strains carry none of these results.

When during an antibiotic course was LGG tested?

The pooled trials gave LGG to people while they were taking antibiotics, to prevent diarrhea from starting. They did not test whether it rebuilds gut bacteria afterward; for that, diet and time do most of the work.

Is Lacticaseibacillus rhamnosus GG the same as LGG?

Yes. The genus name changed; the strain is the same. Look for "GG" after the species name.

All probiotic strains · Strain-to-evidence lookup · Medical disclaimer

General information, not medical advice. Probiotic effects are strain-specific and modest; talk to a clinician about new, severe or persistent symptoms.