Lactate promotes longevity through redox-driven lipid remodeling in Caenorhabditis elegans.

Lactate has emerged as a key metabolite involved in multiple physiological processes, including memory formation, immune response regulation, and muscle biogenesis. However, its role in aging and cellular protection remains unclear. Here, we show that lactate promotes longevity in C. elegans through a mechanism that requires early-life intervention, indicating a hormetic priming effect. This pro-longevity action depends on its metabolic conversion via LDH-1 and NADH, which drives redox-dependent metabolic reprogramming. Multi-omics approaches revealed that lactate induces early-stage metabolic adaptations, with a strong modulation of lipid metabolism, followed by late-life transcriptional remodeling. These shifts are characterized by enhanced stress response pathways and suppression of energy-associated metabolic processes. Our genetic screening identified sir-2.1/SIRT1 and rict-1/RICTOR as essential for lactate-mediated lifespan extension. Our findings establish lactate as a pro-longevity metabolite that couples redox signaling with lipid remodeling and nutrient-sensing pathways. This work advances our understanding of lactate's dual role as a metabolic intermediary and geroprotector signaling molecule, offering insights into therapeutic strategies for age-related metabolic disorders.