INTRODUCTION: The dawn phenomenon (DP), characterized by early morning hyperglycemia, poses a significant challenge in diabetes management and is associated with increased glycemic variability and long-term complications. Despite its clinical impact, effective therapeutic strategies remain limited. Chiglitazar, a novel pan-PPAR agonist, has demonstrated benefits in improving lipid metabolism and insulin sensitivity, but its potential role in mitigating DP remains unexplored. This study evaluates the regulatory effect of chiglitazar on DP and investigates its possible mechanisms beyond lipid modulation. METHODS: This retrospective observational study included 22 hospitalized diabetic patients who received chiglitazar (20 mg). Blood glucose levels at 3:00 a.m. and fasting glucose levels over three consecutive days were measured pre- and post-treatment, and the dawn phenomenon intensity was calculated. Lipid profiles were assessed to explore potential correlations with glucose changes. RESULTS: Following chiglitazar administration, significant reductions were observed in LDL-C (43.82 ± 18.27 vs. 36.97 ± 16.90, p <
0.05), FFA (6.00 ± 2.38 vs. 5.06 ± 1.77, p <
0.05), mean 3:00 a.m. blood glucose (Z = - 2.03, p <
0.05), and fasting blood glucose (Z = - 2.96, p <
0.05). DP intensity also significantly improved (Z = - 3.48, p <
0.01). However, no significant correlation was found between glucose improvements and lipid profile changes (p >
0.05), suggesting an alternative mechanism of action. CONCLUSIONS: Chiglitazar effectively reduces DP intensity and improves glycemic control, independent of its effects on lipid metabolism. These findings suggest a potential link between chiglitazar's mechanism and circadian rhythm regulation, possibly through the modulation of REV-ERB nuclear receptors. Further research is needed to confirm this hypothesis and evaluate the long-term clinical benefits of chiglitazar in diabetes management.