Meet the strains
Two world-leading probiotics. Clinically documented in over 500 human studies and 2,500 scientific publications worldwide - the most researched probiotic strains on earth.
Up to
+35%
Up to
+61%
Up to
-32%
Bifidobacterium animalis subsp. lactic, BB-12®
Clinically validated for digestive comfort and immune balance.
Up to
70%
Up to
50%
Up to
50%
Lacticaseibacillus rhamnosus, LLG®
The world's most documented probiotic strain - trusted for immune, gut, and barrier support.
Strain specific clinical studies
LGG Clinical Studies
| No. | Benefit Area | Strain | Population | Study-based Claim (Consumer language) | Study Type | Number of Participants | Duration | Mechanism of Action | Short Reference | Reference (PubMed link) | Study-based Claim (Scientific language) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Digestive health (infections) | LGG® | Daycare children | Helps reduce colds and tummy upsets in kids at daycare. | RCT | 571 | 7 months | ↑ mucosal IgA; barrier support; immune modulation (hypothesis) | Hatakka et al., 2001 | PMID: 11387176 | Reduced incidence of GI and respiratory infections and fewer antibiotic courses in daycare children. |
| 2 | Dermatological health (eczema prevention) | LGG® | High-risk infants | Supports healthy skin by lowering the risk of eczema in babies. | RCT + follow-up | 159 | Maternal last 4 wks pregnancy + 6 mo infant; follow-up 4 y | Early immune training; Th1/Th2 balance; ↑ Tregs; ↓ pro-inflammatory cytokines (hypothesis) | Kalliomäki et al., 2001/2003 | PMID: 11297958 / PMID: 12788576 | Perinatal LGG reduced incidence of atopic eczema in high-risk infants; preventive effect persisted to 4 y. |
| 3 | Immune health (URTIs) | LGG® | Daycare children | Helps reduce common colds in kids. | RCT | 281 | 3 months | ↑ mucosal IgA; antiviral pathways (hypothesis) | Hojsak et al., 2010 | PMID: 19896252 | Lower risk of URTIs vs placebo; LGG recommended in daycare (RCT). |
| 4 | Gut barrier function | LGG® | Human enteroids/colonoids (ex vivo) | Supports a healthy gut lining. | Translational model | N/A | Short-term assays (hours-days) | Secreted factors; TJ protein preservation; anti-inflammatory signaling | Han et al., 2019 | PMID: 30040527 | LGG prevented IFN-γ-induced tight-junction disruption and permeability increases in human enteroids/colonoids. |
| 5 | Gut-brain axis (cognition) | LGG® | Middle-aged & older adults | May support aspects of cognitive performance in older adults. | RCT | 68 (2020); 113 (2022) | 12 weeks | Microbiota-tryptophan/indole signaling; ↓ inflammation (hypothesis) | Sanborn et al., 2020/22 | PMID: 33223831 / PMID: 35617704 | LGG improved cognition in at-risk adults (2020), but follow-up trial in active adults was neutral. |
| 6 | Gut-brain axis (neurodevelopment) | LGG® | Infants → adolescence | Early LGG linked to fewer ADHD/Asperger cases. | RCT follow-up | 75 (subset of 159) | 6 mo intervention + 13 y follow-up | Early microbial-immune-neurodevelopment programming (hypothesis) | Pärtty et al., 2015 | PMID: 25760553 | At 13 y, ADHD/AS diagnoses 17% placebo vs 0% LGG group (pilot follow-up). |
| 7 | Micronutrient synthesis (Trp→B3) | LGG® | Preclinical + ex vivo | Emerging science: LGG may help generate vitamin-B3 metabolites. | Mechanistic | N/A | 2–8 wks (animal); hrs–days (cell) | Trp → nicotinamide/methyl-nicotinamide; TJ protection | Suntornsaratoon et al., 2024 | PMID: 38641207 | LGG + dietary tryptophan stimulated methyl-nicotinamide; protected against colitis (models). |
BB-12 Clinical Studies
| No | Benefit Area | Strain | Population | Study-based Claim (Consumer language) | Study Type | Number of Participants | Duration | Mechanism of Action | Short Reference | Reference (PubMed link) | Study-based Claim (Scientific language) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 8 | Digestive health (regularity) | BB-12® | Adults w/ low stool frequency | Helps improve regularity and ease of bowel movements. | RCT | 124 | 4 weeks | ↑ Bifidobacterium; ↑ stool bulk | Eskesen et al., 2015 | PMID: 25240034 | BB-12 increased defecation frequency vs placebo in adults with low stool frequency. |
| 9 | Immune health (vaccine response) | BB-12® | Healthy adults | Supports the body’s defenses by enhancing vaccine response. | RCT | 211 | 6 weeks (2 before + 4 after vaccine) | ↑ dendritic/B-cell activity; ↑ IgA & IgG | Rizzardini et al., 2012 | PMID: 21899798 | BB-12 increased systemic and mucosal antibody responses to influenza vaccination. |
| 10 | Immune health (RTIs) | BB-12® | Infants | Helps reduce respiratory infections in babies. | RCT | 662 | 24 months (1 mo → 2 y) | ↑ mucosal sIgA; innate tone (hypothesis) | Taipale et al., 2016 | PMID: 26372517 | Infants receiving BB-12 had fewer RTIs vs controls (RR 0.87; P=0.033). |
| 11 | Anti-inflammatory effects (matrix-dependent) | BB-12® | Healthy adults | Can help calm inflammatory signaling; effect depends on product format. | RCT crossover | 36 | 4 wks per intervention + washout | ↓ TLR-2; ↓ TNF-α secretion | Meng et al., 2017 | PMID: 26621631 | BB-12 in yogurt smoothie lowered PBMC TNF-α secretion & TLR-2 expression. |
| 12 | Gut microbial balance | BB-12® | Healthy adults | Helps increase beneficial bifidobacteria in the gut. | RCT crossover | 36 | 4 wks per arm | Colonization; competitive exclusion | Ba et al., 2021 | ASM mSphere | BB-12 in yogurt smoothie ↑ B. animalis abundance in feces; overall microbiota stable. |
Your questions, answered.
Because clinically proven should also be clear-cut.
Are the Gutcultured bacteria strains clinically researched?
Yes. Both strains have extensive peer-reviewed clinical research and documentation, covering digestive health, immune support, infant health, antibiotic-associated outcomes and overall microbiome function.
Do our strains survive stomach acid and bile?
Yes. BB-12® and LGG® are documented for surviving harsh upper digestive conditions and effectively reaching the intestines alive.
How many CFUs does Gutcultured contain?
Each Gutcultured daily dose contains a clinically validated daily dose of 10 billion CFU, guaranteed. We focus on documented effectiveness, not inflated CFU counts that don’t correlate with real-world benefits.
Are the bacteria strains safe?
Yes. Safety profiles for BB-12® and LGG® are excellent and supported across diverse populations, women who are pregnant and breastfeeding, children from age 3 and long-term use. We still recommend discussing any new supplement with your healthcare provider.
Are there published studies I can read?
Yes. BB-12® and LGG® have hundreds of peer-reviewed studies, including placebo-controlled trials. We reference key publications on this page for transparency.