Implications of GLP-1 Receptor Agonist on Thyroid Function: A Literature Review of Its Effects on Thyroid Volume, Risk of Cancer, Functionality and TSH Levels

Abstract

The increasing utilization of Glucagon-like Peptide-1 receptor agonists (GLP-1 RAs) in managing type 2 diabetes mellitus has raised interest regarding their impact on thyroid function. In fact, while these agents are well known for their efficacy in glycemic control and weight management, their association with thyroid disorders requires clarification due to the complex interplay between thyroid hormones and metabolic pathways. Thyroid dysfunction commonly co-occurs with metabolic conditions such as diabetes and obesity, suggesting a profound interconnection between these systems. This review aims to contribute to a deeper understanding of the interaction between GLP-1 RAs and thyroid dysfunction and to clarify the safety of GLP-1 RAs in diabetic patients with thyroid disorders. By synthesizing existing evidence, this review highlights that, despite various studies exploring this topic, current evidence is inconclusive, with conflicting results. It is important to note that these drugs are relatively recent, and longer-term studies with larger sample sizes are likely needed to draw clearer conclusions. Currently, no existing guidelines provide definitive directions on this clinical issue; however, it is advisable to include thyroid function tests in the routine screening of diabetic patients, particularly those treated with GLP-1 Ras, with the goal of optimizing patient care and management.

Keywords: GLP-1 receptor agonists; TSH; diabetes; hyperthyroidism; hypothyroidism; thyroid cancer.

Figure 1

GLP-1 facilitates insulin secretion (BioRender.com). Dipeptidyl peptidase 4 (DPP-4) metabolizes GLP-1 by cleaving the peptide chain between Ala-8 and Glu-9.

Figure 2

Schematic illustration of the intracellular signaling cascade where GLP-1 stimulates insulin release in beta-cells.