Cellular senescence — the state of irreversible cell-cycle arrest — distorts endocrine communication through at least four distinct mechanisms: altering cell identity, corrupting stimulus-secretion coupling, disrupting circadian secretory timing, and hijacking local immune and paracrine signaling. The strongest mechanistic evidence comes from pancreatic β-cells and adrenal zona fasciculata cells, where senescence phenotypes map directly onto measurable endocrine dysfunction. Critically, β-cell senescence is not monolithic — some senescent states preserve insulin production or even support β-cell maturation and immune tolerance, while others propagate inflammatory cascades that impair glucose regulation.
This framing reorients how geroscience should approach endocrine aging. The dominant senolytics narrative — that clearing senescent cells is broadly beneficial — collides here with evidence that selectively eliminating β-cell senescence could eliminate protective subpopulations. The analysis also highlights a persistent methodological gap: no single biomarker reliably identifies senescent endocrine cells across tissues, making clinical translation premature. Pituitary and thyroid data offer narrower mechanistic windows, while parathyroid and pineal gland findings remain largely inferential at the axis level rather than the cellular. For adults, the practical implication is that broad senolytic interventions (dasatinib, quercetin, navitoclax) may carry tissue-specific risks not captured in current trials. The field urgently needs lineage-resolved, multi-domain senescence profiling paired with dynamic hormone readouts before therapeutic targeting becomes safe or precise.
