Buck Institute researchers have discovered and are developing a novel, non-invasive biomarker test that can be used to measure and track performance of senolytics: a class of drugs that selectively eliminate senescent cells. The discovery is expected to play a major role in efforts to develop treatments that would battle a myriad of chronic age-related conditions that range from arthritis to lung disease to Alzheimer’s disease and glaucoma. This biomarker is a unique signaling lipid metabolite, normally exclusively intracellular, but is released when senescent cells are forced to die. This metabolite is detectible in blood and urine, making non-invasive testing possible. With a growing list of senolytic drugs in development, detecting this metabolite via a companion test could verify performance of senolytic candidates.