Background: Extending healthspan—the years lived in good health—is a major public health priority. This review synthesised evidence from randomised controlled trials assessing interventions that may enhance healthspan in humans, focusing on intrinsic capacity and quality of life. Methods: The review was registered (CRD420251015780) and conducted in line with PRISMA guidelines. Systematic searches of MEDLINE, EMBASE, and grey literature were performed to identify studies evaluating interventions targeting improvements in intrinsic capacity or quality of life. The initial search included studies published up to 21 March 2025, with an update capturing additional studies from 22 March 2025 to 16 October 2025. Results: A total of 1,960 records were screened, of which 15 studies (n = 4,656 participants) met the inclusion criteria. The included studies showed substantial heterogeneity in intervention types, including exercise-only interventions (n = 7), multidomain approaches (n = 6; all incorporating exercise), oral supplementation (n = 2), and caloric restriction (n = 1). Most studies (11/15) reported improvements in intrinsic capacity and/or quality of life following exercise-based or multidomain interventions. Evidence for other intervention types remained limited and inconclusive. Conclusion: Exercise interventions, whether delivered alone or as part of a multidomain strategy, appear to have beneficial effects on intrinsic capacity and quality of life. Further high-quality research is needed to assess the impact of other interventions and to confirm findings across broader populations.