Diversity and Dosage Determine the Efficacy of the Probiotic SYN-53 in Allergic Rhinoconjunctivitis: A Randomized, Double-Blind, Placebo-Controlled Trial.

ABSTRACT: SYN-53, a multi-strain probiotic food supplement, was recently shown to significantly alleviate allergic rhinoconjunctivitis (ARC) and its symptoms. The diversity and dosage of bacterial strains administered via SYN-53 have been proposed as key drivers of its efficacy. The aim of this study was to assess the role of bacterial diversity and dosage by comparing SYN-53 to a low dose variant (SYN-53-LD), a low diversity variant (SYN-4), and a placebo in the management of ARC. This double-blind, parallel-group, placebo-controlled clinical trial included subjects with moderate-to-severe grass pollen allergy. Following baseline exposure in an allergen exposure chamber (AEC), 166 subjects were randomized to undergo three weekly 3-day intake cycles of SYN-53, SYN-53-LD, SYN-4, or placebo, followed

SUBMITTER: Bergmann KC 

PROVIDER: S-EPMC12666746 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature