This pilot clinical study aims to investigate the potential effects of tirzepatide on biological aging in older adults. In this novel study, 90 adults aged 55-70 years with an indication for tirzepatide weight-loss therapy will be randomized to receive either tirzepatide 2.5 mg subcutaneously (SC) weekly or no drug for 24 weeks, followed by 12 weeks off the drug. Since tirzepatide is already recognized as a highly effective weight-loss agent in this population, the primary focus will not be on measuring weight loss. Instead, the study will document the effects of tirzepatide on markers of aging, physical function, and overall health.