About LGG
Lactobacillus rhamnosus GG (LGG) is among the most-studied probiotic strains in humans. Isolated in 1983 at Tufts by Gorbach and Goldin (patent filed 1985, hence 'GG'). Reclassified in 2020 as Lacticaseibacillus rhamnosus. Strongest clinical evidence for pediatric antibiotic-associated diarrhea prevention. Acute gastroenteritis benefit shown in European cohorts but null in the 2018 Schnadower NEJM trial in US children. Marketed primarily as Culturelle. Survives gastric acid and adheres to intestinal mucosa. No established RDA/UL.
What LGG supports
- Reduces risk of antibiotic-associated diarrhea (Cochrane 2019, Szajewska 2015)
- Reduces duration of acute infectious diarrhea in children (effect strongest in European cohorts; null in US 2018 NEJM trial)
How much LGG to take
The RDA prevents deficiency. The effective range is what clinical trials used to actually move the outcome.
Effective
5–40
billion_cfu
Clinical range 5-40 billion CFU/day. Pediatric acute gastroenteritis benefit requires ≥10 billion CFU/day (Szajewska 2019 meta-analysis). AAD prevention: 5-40 billion CFU/day (Goldenberg Cochrane 2019). Dose is measured in CFU, not mg.
Clinical evidence
Moderate clinical evidence. Strong evidence for pediatric AAD prevention; AGE benefit varies by population (positive in Europe, null in US NEJM 2018); null for atopic dermatitis prevention
NIH Fact Sheet