IGF-1 signaling operates through a previously unrecognized temporal switch that determines whether cells repair or senesce. Acute IGF-1 exposure promotes tissue homeostasis and repair, while chronic activation triggers stable senescence through ROS-mediated DNA damage and p53/p21 pathway activation. The key mediator is IGF-binding protein-5 (IGFBP-5), which amplifies senescence in vascular and stromal cells by connecting coagulation and inflammatory signals to cellular arrest. This biphasic mechanism explains the longevity paradox observed in human conditions like Laron syndrome (IGF-1 deficiency with extended lifespan) versus acromegaly (IGF-1 excess with reduced longevity). The discovery that extracellular vesicles can bypass normal IGFBP regulation adds complexity to anti-aging interventions. This model fundamentally reframes IGF-1 from a simple growth factor to a temporal molecular switch. Rather than blanket IGF-1 suppression, optimal longevity strategies may require precisely timed modulation combined with targeted senolytic therapies. The research suggests personalized approaches based on individual IGF-1/IGFBP profiles could optimize healthspan extension while preserving beneficial repair functions.