The valorization of culinary by-products into functional bioactive resources represents a significant advancement in sustainable biotechnology. This study characterizes an extract derived from “battuto toscano” by-products, a traditional blend of garlic, onion, carrot, and celery trimmings, recovered through circular economy principles. Comprehensive antioxidant profiling was performed alongside biological evaluations on human cell lines and anti-glycation assays. Results from Folin–Ciocalteu, FRAP, and TEAC assays confirmed a high concentration of secondary metabolites with significant scavenging capacity. In vitro testing on primary human fibroblasts and HaCaT keratinocytes revealed a concentration- and time-dependent biological response, with lower concentrations showing better compatibility and transiently enhancing HaCaT metabolic activity. Furthermore, BTE reduced AGE-associated fluorescence in the BSA–glucose model, particularly at 5 mg/mL, supporting its potential anti-glycation activity. These findings establish “battuto toscano” by-products as a reservoir of sustainable biomolecules. This study offers a transformative resource for the pharma/nutraceutical sectors by bridging culinary tradition with biomedical innovation.