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Evidence-Based Supplement Research
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Myth-buster

A multi-strain probiotic containing BB-12 did not reduce respiratory infections in 118 children, contradicting earlier studies that suggested a benefit.

This null result from a randomized trial pushes back against the prevailing evidence that BB-12 helps prevent colds and flu, but because the study used a blend of strains, it doesn't rule out that BB-12 alone might still work — the picture is now genuinely contested.

In a randomized controlled trial of 118 children in daycare settings, a multi-strain probiotic that included Bifidobacterium animalis subsp. lactis BB-12 had no statistically significant effect on upper respiratory infections, even though it did reduce gastrointestinal infections after about eight weeks. This contradicts five out of six prior studies that found BB-12 beneficial for respiratory health, meaning the evidence is now mixed and the question remains open.

Where this fits in the evidence

Pillser has synthesized 6 studies on Bifidobacterium animalis subsp. lactis BB-12 for Reduced Upper Respiratory Infections — overall evidence strength: Moderate.

Across 6 studies, 5 reported beneficial effects of Bifidobacterium animalis subsp. lactis BB-12 on reducing upper respiratory infections, with effect sizes ranging from small to large. Statistically significant findings were observed in 4 studies, including a meta-analysis (moderate effect, RR=0.79) and RCTs in infants (small effect) and young children (moderate effect). The most studied population is healthy infants and young children, with a specific dose of 10 billion CFU/day reported in one high-quality study.

The study

Multi-Strain Probiotic and Common Infections in Early Childhood Education Settings: A Randomised Controlled Trial.

  • Randomized Controlled Trial (RCT)
  • n = 118
  • 2026-01-23
  • Journal of paediatrics and child health
More on Bifidobacterium animalis subsp. lactis BB-12More on Reduced Upper Respiratory Infections

This is a plain-language summary of a research finding, not medical advice. Pillser surfaces research signals to help you decide what's worth investigating — always consult a qualified professional before changing what you take.

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