Vitamin D Deficiency and Polycystic Ovary Syndrome: Molecular Mechanisms and Siddha-Based Integrative Therapeutic Insights

Background: Vitamin D (VD) plays a pivotal role in reproductive physiology and endocrine regulation. Deficiency of VD has been closely associated with metabolic, hormonal, and inflammatory disturbances characteristic of polycystic ovary syndrome (PCOS). Objective: The study aimed to explore the molecular and clinical mechanisms underlying VD deficiency in PCOS and to present evidence-based Siddha herbal interventions that may optimize VD activity and reproductive health outcomes. Methods: A structured literature synthesis was conducted using PubMed, Scopus, and Siddha classical texts. Recent clinical trials, molecular studies, and ethnopharmacological reports were analyzed to establish integrative correlations between VD function, insulin sensitivity, and herbal mechanisms. Results: VD deficiency was shown to disrupt insulin receptor expression, glucose transport, and ovarian folliculogenesis. Supplementation improves menstrual regularity, ovulation, and lipid profiles. Siddha herbs rich in flavonoids, phytoestrogens, and minerals exhibit molecular mechanisms analogous to VD-enhancing insulin sensitivity, modulating androgen levels, and promoting bone metabolism. Conclusion: An integrative model combining VD optimization with Siddha-based herbal supplementation may represent a promising adjunctive approach in the prevention and management of PCOS. Further clinical translational studies are warranted to validate these mechanisms.