OBJECTIVE: To investigate the relationship between leptin levels, insulin resistance (measured by HOMA), and clinical outcomes related to pain, disability, and shoulder range of motion (ROM) in patients with frozen shoulder (FS). METHODS: This cross-sectional study included 34 patients diagnosed with FS. Leptin and HOMA levels were measured and analysed in relation to pain and disability scores, as assessed by the Shoulder Pain and Disability Index (SPADI), along with shoulder ROM (flexion, extension, abduction, adduction, and internal/external rotation). Linear regression models were used to evaluate associations between leptin, HOMA, and clinical outcomes, adjusting for potential confounders such as age and sex. RESULTS: Higher leptin levels were significantly associated with increased SPADI pain (R CONCLUSION: Elevated leptin and insulin resistance levels were linked to greater pain, disability, and decreased ROM in patients with FS. These findings underscore the potential role of metabolic and inflammatory pathways in FS pathogenesis and highlight the importance of considering lifestyle interventions targeting leptin and insulin regulation as adjuncts to traditional management strategies for this condition. SIGNIFICANCE STATEMENT: Elevated levels of leptin and HOMA (insulin resistance) are significantly associated with increased pain and disability in patients with frozen shoulder, as measured by SPADI scores. Higher leptin and HOMA levels are also associated with reduced range of motion, particularly in shoulder flexion. Targeting metabolic and inflammatory markers such as leptin and insulin resistance could inform new therapeutic approaches for managing frozen shoulder, with potential implications for treatment strategies in other inflammatory musculoskeletal conditions.