Chronotherapy in Inflammatory Bowel Disease: Biological Rationale, Human Evidence, and a Clinical Implementation Framework.

Inflammatory bowel disease (IBD) is a chronic condition driven by a dysregulated immune response to the gut microbiome in genetically susceptible individuals. This process may be influenced by the circadian rhythm, the body's internal 24-h clock that coordinates physiology with the day-night cycle. Disruption of this rhythm, whether from behavior or intrinsic dysfunction, can disturb intestinal homeostasis and promote inflammation. Chronotherapy applies this concept clinically by aligning medical treatment with circadian timing to optimize efficacy and reduce adverse effects. There is growing evidence suggesting the importance of this approach for drug metabolism, immune activity, and symptom patterns, offering a new dimension of personalization beyond medication choice alone. This review summarizes the biological links between circadian regulation and intestinal inflammation, highlights emerging human data supporting time-based treatment strategies, and proposes a practical framework for integrating chronotherapy into routine IBD management. By considering when a therapy is delivered in addition to what therapy should be used, clinicians may enhance treatment response, limit toxicity, and improve overall disease control.