Background. Intestinal dysbiosis and low-grade metabolic endotoxemia have been identified as contributing mechanisms to the development of obesity, insulin resistance, and metabolic syndrome. Bifidobacterium animalis ssp. lactis B420 is a probiotic strain with preclinical and clinical evidence of gut microbiome modulation with metabolic repercussions. Objective. To critically review the available evidence on the efficacy and safety of the B420 strain, marketed in Argentina as Floragut®, in weight management, body composition, and gastrointestinal health. Methods. A narrative review of the literature indexed in PubMed and PMC was conducted, supplemented with preclinical mechanistic studies and an analysis of availability and cost in the Latin American market. Randomized, double-blind, placebo-controlled clinical trials were prioritized. Results. The pivotal six-month trial by Stenman et al. (2016; n=225) demonstrated statistically significant reductions in total body fat mass, trunk fat mass, waist circumference, and spontaneous caloric intake, without concomitant dietary intervention. Proposed mechanisms include strengthening of intestinal epithelial tight junctions, decreased lipopolysaccharide translocation, promotion of Akkermansia muciniphila, and moderate stimulation of endogenous GLP-1. The safety profile was favorable, with mild and self-limiting adverse events. A documented limitation is the lack of protection against NSAID-induced acute gastrointestinal injury. Conclusions. The evidence supports a modest but consistent effect of B420 on markers of adiposity and metabolic function in overweight adults. Limitations of the body of evidence include a still small number of human clinical trials, lack of efficacy against NSAID-induced acute mucosal injury, and documented economic barriers to access in Latin American markets. Further trials with diverse populations and long-term follow-up are required. Keywords: Bifidobacterium animalis lactis B420; probiotics; gut microbiome; obesity; metabolic endotoxemia; GLP-1; Akkermansia muciniphila; body composition.