IGF1 and acne: Mechanistic studies have suggested that selected probiotic strains may influence acne-related pathways—such as reducing pro-inflammatory cytokines (IL-1β, IL-6, TNF-α), enhancing epithelial barrier function, and modulating IGF-1/mTORC1 signaling—although these mechanistic insights are not sufficient to infer clinical benefit on their own [25,26,27,28,30].