Intermittent Fasting and Hormonal Regulation: Pathways to Improved Metabolic Health

Intermittent fasting (IF), a temporal dietary pattern, has garnered interest in improving anthropometric and metabolic markers. Beyond this, IF appears to recalibrate hormonal circadian rhythms and reshape gut microbiota—two key intermediaries through which IF exerts effects on endocrine, inflammatory, and oncogenic pathways. This review synthesizes research findings of IF on key endocrine systems and outlines its potential implications for oncogenic risk. We primarily examine the effects of IF on hormonal regulation with a particular focus on its relevance to metabolic and oncogenic health outcomes. We explored hormonal alterations induced by various IF protocols and discussed their physiological implications. Controlled observations or interventional studies in both human and animal models were included. Evidence indicates that IF exerts systemic effects on hormonal rhythmicity, including insulin, thyroid hormones, glucocorticoids, and sex hormones, potentially re-establishing homeostatic endocrine function. Moreover, IF influences cancer-related pathways via modulation of endocrine axes and attenuation of inflammatory markers. These mechanisms offer a theoretical basis for IF's potential in attenuating metabolic dysfunction and cancer risk. However, the current research is limited by variations in study designs, short durations, limited cohorts, and population-specific findings, restricting generalizability and applicability. Ultimately, IF represents a multifaceted dietary strategy with the potential to synchronize circadian and hormonal systems, positioning it as a promising intervention in metabolic and endocrine-related conditions. However, whether long-term IF can modulate specific hormonal axes without overt physiological side effects, including sex-specific effects, remains unclear. To establish its clinical relevance and therapeutic safety, validation through well-designed and large-scale human trials is imperative.