Biomarkers play a crucial role in longevity research, offering valuable insights into the aging process and potential interventions. From telomere length to levels of inflammation and oxidative stress, biomarkers provide indicators of overall health and potential age-related diseases. One such biomarker used for longevity purposes is chloride, a key electrolyte involved in maintaining cellular function and balance. Research suggests that chloride levels may be associated with aging and age-related diseases, providing a potential marker for assessing biological age and determining interventions for promoting healthy aging. By understanding and monitoring chloride levels, researchers can gain valuable insights into the aging process and develop strategies for extending healthspan and lifespan.