Benefits
Bowel movement frequency in adults with infrequent bowel movements
In 1,248 adults with infrequent bowel movements and mild discomfort, 1 or 10 billion CFU a day for 4 weeks did not reach significance on the main frequency responder analysis, and discomfort relief did not differ. Average weekly frequency, a supportive analysis, was higher than on placebo. The maker funded the trial. In 36 healthy adults, gut transit time did not change.
Crying time in breastfed infants with excessive crying
In two placebo-controlled trials in breastfed infants with colic (80 and 192 infants), 1 billion CFU a day for 3 to 4 weeks led to more infants having their crying time cut by at least half, the main outcome in both, along with fewer crying episodes. One trial was funded by the drops' maker and the other had a Chr. Hansen author.
Digestive health in formula-fed infants in child care
In a 12-week trial in 201 healthy infants aged 4 to 10 months at child care centers, formula with BB-12 was followed by fewer diarrhea episodes than formula without probiotics (0.13 versus 0.31 per infant). Respiratory illness did not differ, and an L. reuteri formula tested in the same trial did better on more measures.
Immune support in infants and young children
In 109 healthy infants, a BB-12 tablet (10 billion CFU a day) was followed by fewer respiratory infections than placebo (65% versus 94% by 8 months), one of two primary outcomes in the full text, though only the 69 infants who finished were analyzed and the trial registry lists infections as secondary. In 210 children at day care, BB-12 at 1 billion CFU for 3 months did not change infections, the main outcome.
Antibody response after a seasonal vaccine (marker study)
In 211 healthy adults, at least 1 billion CFU a day in a capsule for 6 weeks gave larger rises in vaccine-specific blood IgG and saliva IgA than placebo, with no change in cytokines or innate immune measures. Antibody levels are markers, not illness outcomes, and the maker sponsored the trial and two authors worked there.
Digestive comfort during antibiotic courses
In 255 healthy children aged 3 to 12 taking antibiotics, mostly amoxicillin,, a yogurt with BB-12 for 14 days did not lower diarrhea, the main outcome (2% in both groups), in a trial funded by the NIH. In adults on amoxicillin/clavulanate, fecal acetate and gut bacteria recovered faster on BB-12 yogurt, which are markers only.
Mechanism of action
Passage through the gut
BB-12 was recovered in the stool of 62% of infants given it daily in a 7-month trial. In a crossover study in healthy adults, B. animalis made up a larger share of fecal bifidobacteria after BB-12 smoothies, but overall gut bacteria, transit time and fecal short-chain fatty acids did not change.
Gut bacteria and fecal acids during antibiotics (human markers)
In adults taking amoxicillin/clavulanate, fecal acetate returned to baseline by day 30 with BB-12 yogurt but stayed lower with control yogurt, and the fall in microbial diversity was smaller. In children on narrower antibiotics, gut bacteria recovered by day 14 in both groups, and diarrhea did not differ.
Antibody and innate immune markers
In healthy adults, vaccine-specific antibodies in blood and saliva rose more on BB-12 than placebo, while cytokines did not change. In breastfed infants with excessive crying, fecal butyrate, secretory IgA and antimicrobial peptides rose on BB-12. How these markers relate to symptoms or illness is not known.
Clinical trials
Randomized, double-blind, placebo-controlled, parallel-group trial (ISRCTN18128385); after a 2-week run-in, BB-12 at 1 or 10 billion CFU a day or placebo capsules for 4 weeks. Two primary outcomes: defecation frequency and gastrointestinal well-being. Funded in full by Chr. Hansen, the strain's maker; four of six authors worked there and the other two consulted for it (Eskesen et al. 2015, Br J Nutr)
1,248 healthy adults with low defecation frequency and abdominal discomfort.
The prespecified main analysis of the frequency primary outcome, the odds of a frequency above baseline at least half the time, was 1.31 (95% CI 0.98 to 1.75, p=0.071) and not significant; it was significant per protocol in the 1 billion group. The other primary outcome, global relief of abdominal discomfort, did not differ. Average weekly frequency, a predefined supportive analysis, was higher on BB-12 at every week (p=0.0065), similar at both doses, and a post hoc stricter definition (a rise of at least 1 day a week) gave odds of 1.55 (p=0.0003).
Randomized, double-blind, placebo-controlled, parallel-group study with separate arms: BB-12 in a capsule or L. casei 431 in a dairy drink, each at a minimum of 1x10^9 CFU once daily, against matching placebos for 6 weeks, with flu vaccination after 2 weeks; primary outcomes vaccine-specific plasma IgG, IgG1 and IgG3 (ISRCTN64739181); sponsored by Chr. Hansen (Rizzardini et al. 2012, Br J Nutr)
211 healthy adults, 56% women, mean age 33.
In the BB-12 arm, rises in vaccine-specific plasma IgG, IgG1 and IgG3 were greater than on placebo (P < 0.001), more people had at least a 2-fold rise in specific IgG (P < 0.001), and the fold rise in vaccine-specific saliva secretory IgA was greater (P = 0.017). Plasma cytokines and innate immune measures did not differ. Influenza-like illness was rare in all groups and no infections were diagnosed, so illness was not tested. Two of the six authors worked for Chr. Hansen and two consulted for it.
Double-blind, randomized, placebo-controlled study in Chengdu, China, from April 2016 to October 2017; after a 1-week run-in, BB-12 at 1x10^9 CFU a day or placebo for 3 weeks; primary outcome the share of infants whose daily crying and fussing time fell by at least 50% from baseline. One author worked for Chr. Hansen; funding is not stated in the abstract (Chen et al. 2021, Benef Microbes)
192 full-term breastfed infants under 3 months of age meeting Rome III criteria for infant colic.
More infants on BB-12 reached at least a 50% cut in crying and fussing time (P < 0.001). Crying episodes fell from 10.0 to 5.0 a day on BB-12 versus 10.5 to 7.5 on placebo (P < 0.001), and daily sleep rose by 60.7 versus 31.9 minutes (P < 0.001). Fecal beta-defensin 2, cathelicidin, secretory IgA, calprotectin and butyrate were higher on BB-12, and parent quality of life scores were better.
Randomized, double-blind, placebo-controlled trial (NCT02988791); BB-12 (DSM 15954) at 1x10^9 CFU a day in an oil and maltodextrin suspension or a matching placebo for 28 days, alongside parental reassurance; primary outcome the share of infants with at least a 50% drop in mean daily crying time. Funded by Sofar S.p.A., the product's maker, which the paper states had no role in the analysis; no author is listed at Chr. Hansen (Nocerino et al. 2020, Aliment Pharmacol Ther)
80 otherwise healthy, exclusively breastfed infants aged 7 weeks or less with infant colic (40 per group).
At 28 days, 80% of the BB-12 group and 32.5% of the placebo group had at least a 50% drop in crying time in the intention-to-treat analysis (80.0% versus 31.5% per protocol; P < 0.0001). Crying episodes fell by 4.7 versus 2.3 a day (P < 0.05). The abstract reports a larger fall in stool frequency on BB-12, but the results section found no difference in its change by day 28, and stool consistency did not differ. Fecal butyrate, beta-defensin 2, cathelicidin and secretory IgA rose and calprotectin fell on BB-12.
Double-blind, randomized, placebo-controlled trial in Finland; a BB-12 tablet with xylitol (10 billion CFU a day) or a xylitol-only control tablet given by slow-release pacifier or spoon from 1 to 2 months until 8 months of age; primary outcomes reported respiratory infections and doctor-diagnosed ear infections, in a substudy of an oral health trial (NCT00638677) whose registry lists infections as secondary. Reported gastrointestinal symptoms did not differ, and BB-12 was recovered in the stool of 62% of infants given it. Chr. Hansen donated the BB-12 and two Chr. Hansen authors ran the stool analysis; the paper states that the companies gave no financial support (Taipale et al. 2011, Br J Nutr)
109 healthy newborn infants (55 BB-12, 54 control); only the 69 who completed follow-up to 8 months were analyzed (34 BB-12, 35 control).
Fewer infants in the BB-12 group had respiratory infections (65% versus 94%, 22 of 34 versus 33 of 35; risk ratio 0.69, 95% CI 0.53 to 0.89, p=0.014). The other primary outcome, doctor-diagnosed ear infection, did not differ (26% versus 17%, P = 0.455), nor did antibiotic use. No adjustment for two primary outcomes is described.
Double-blind, placebo-controlled, randomized trial at 14 child care centers near Beer-Sheva, Israel; formula with BB-12, formula with L. reuteri ATCC 55730, or formula without probiotics for 12 weeks in infants who were not breastfed. Funding was not stated in the abstract (Weizman et al. 2005, Pediatrics)
201 healthy term infants aged 4 to 10 months (73 BB-12, 68 L. reuteri, 60 control).
Compared with control, the BB-12 group had fewer febrile episodes (0.27 versus 0.41) and fewer diarrhea episodes (0.13 versus 0.31 per infant). Rates and duration of respiratory illness did not differ. Only the L. reuteri group also had fewer fever days, clinic visits, child care absences and antibiotic prescriptions.
Randomized, double-blind, placebo-controlled trial; BB-12 at a dose of 10^9 CFU or placebo during a 3-month intervention period; main outcome common gastrointestinal and respiratory infections, analyzed by intention to treat. Funding is not stated in the abstract, and no author is listed at Chr. Hansen (Hojsak et al. 2016, Clin Nutr)
210 healthy children attending day care centers (104 BB-12, 106 placebo).
There were 97 infections on BB-12 and 99 on placebo (incidence rate ratio 1.0014, p = 0.992), and 64.4% versus 61.3% of children had at least one (p = 0.642). Symptom duration, gastrointestinal and respiratory infections counted separately, day care absence and antibiotic use did not differ. The authors concluded that BB-12 had no effect on these infections.
Randomized, placebo-controlled, double-blind trial (PLAY-ON, NCT03181516) run under an FDA investigational new drug application; a strawberry yogurt with BB-12 (at least 10^8 CFU per gram) or the same yogurt without BB-12, eaten daily for 14 days alongside an antibiotic (74% amoxicillin) prescribed for an acute upper respiratory infection. Primary outcome: clinically defined diarrhea. Funded by the NIH (NICHD); the authors declared no competing interests and none worked for Chr. Hansen (Merenstein et al. 2026, Sci Rep)
Healthy children aged 3 to 12 (125 BB-12, 130 control analyzed).
Diarrhea occurred in 3 children (2%) on BB-12 and 2 (2%) on control (p = 0.62), far below the expected 20 to 35%. Loose stools reported as adverse events, a post hoc measure, were 20% versus 14% (p = 0.19), and total adverse events were similar. Gut bacteria returned to baseline by day 14 in both groups. Children on broader-spectrum drugs (amoxicillin/clavulanate, cefdinir or cephalexin) had more diarrhea than those on amoxicillin or penicillin (9.1% versus 0.5%).