The gut-thyroid interplay: Emerging role of gut dysbiosis in thyroid dysregulation

Abstract

The gut-thyroid interplay is a dynamic bidirectional crosstalk among the gut microbiota, thyroid function, and immune regulation. Recent studies highlight the essential role of gut microbial metabolites in regulating thyroid hormone metabolism, immune responses, and intestinal barrier integrity. Gut dysbiosis has emerged as an important contributor to the pathogenesis of autoimmune thyroid disorders (AITD). It leads to increased intestinal permeability, chronic inflammation, oxidative stress, and activation of autoimmunity, thereby leading to Hashimoto's thyroiditis and Graves' disease. Multi-omics studies have revealed disease-specific microbial signatures associated with AITD. Thyroid dysfunction and intestinal disorders frequently coexist, as evidenced by deterioration of the intestinal barrier and increased permeability, which, in turn, stimulates the immune system. Probiotics have therapeutic potential for restoring thyroid homeostasis. Overall, the gut microbiota emerges as a key regulator of thyroid homeostasis, influencing hormone availability and immune tolerance. Understanding this interplay provides novel insights into the mechanisms of thyroid disease and identifies the potential targeted therapeutic strategies. © 2026 Elsevier Inc.