Professor Leonidas H. Duntas is a specialist in Internal Medicine and Endocrinology, serving at the University of Ulm in Germany and the University of Athens in Greece. He focuses on clinical thyroidology, with particular research into the impact of environmental factors, such as selenium and bisphenol A, on thyroid function, thyroiditis, and cancer. His work also explores hypothyroidism treatment, thyroxine variability, and drug interactions. Professor Duntas is an active leader in thyroidology, serving as Secretary of the European Thyroid Association (ETA) and holding roles in the American Thyroid Association (ATA) and European Society of Endocrinology (ESE). He has published over 150 peer-reviewed articles and co-edited the textbook Thyroid and its Diseases. He is a visiting professor at universities in Serbia and serves on the editorial boards of several scientific journals.