Does Probiotics actually make a difference, or is it overhyped?

Probiotics have some of the more consistently positive supplement evidence for a specific, common problem: multiple meta-analyses, including a landmark JAMA meta-analysis and two Cochrane reviews (one in children, one for C. Weighing the data: Probiotics looks well-studied but modest in effect — the evidence is rated strong (75/100), but its estimated impact on longevity is comparatively small (48/100).