About Streptococcus salivarius K12
An oral probiotic (distinct from the dairy starter S. salivarius subsp. thermophilus). The BLIS K12 and M18 strains produce bacteriocins (salivaricins) and have RCTs for reduced streptococcal/viral pharyngitis, otitis media and oral biofilm/halitosis. Strain- and site-specific (oral cavity), not a gut probiotic.
What Streptococcus salivarius K12 supports
- Moderate evidence for throat/ear infection reduction and oral health
- Produces bacteriocins that antagonize oral pathogens
How much Streptococcus salivarius K12 to take
The RDA prevents deficiency. The effective range is what clinical trials used to actually move the outcome.
Effective
1–5
billion_cfu
K12/M18 oral RCTs use ~1-5 billion CFU/day (lozenge). Presence-only when in blends; nominal range.
Clinical evidence
Moderate clinical evidence. Moderate: multiple oral-health RCTs for K12/M18 strains.
NIH Fact Sheet