Distinct effects of tea types and components on circadian rhythm entrainment and clock gene regulation

Circadian disruption is closely associated with sleep and metabolic disorders, yet effective interventions remain limited. As a widely consumed beverage, tea contains diverse bioactive compounds with potential chronobiological effects. Here, we systematically compared six major tea types (oolong, dark, green, black, yellow, and white) and four representative components (theanine, theophylline, epigallocatechin gallate [EGCG], and tea polyphenols) in animal and cellular models of circadian disruption. In mice, white tea markedly accelerated re-entrainment to 6-hour phase advances, while dark and black tea improved adaptation to 6-hour phase delays. Across tissues, dark tea exerted the most prominent modulation of core clock genes. In vitro, tea polyphenols, theophylline, and EGCG prolonged circadian periods in cells and enhanced adaptation to long cycles. Collectively, our findings reveal distinct and context-dependent effects of tea and its components on circadian entrainment and gene regulation, highlighting their potential as natural modulators for mitigating jet lag and circadian-related health disorders.