Prof. Em. Dr. med. Alex Vermeulen (1927–2023)—A Giant in Endocrinology

Alex Vermeulen (1927–2023) was a leading Belgian endocrinologist whose name will forever remain linked to testosterone and androgen metabolism. As a dedicated scientist and clinician, he made seminal contributions to endocrinology throughout his career. These included the development of chromatography and radioimmunoassays of steroid hormones. His work also focused on the biological significance and metabolism of corticosteroids and androgens, and he defined key concepts in the role of steroid hormones in the human menstrual cycle, pregnancy, and menopause. His love for math, endocrinology, and problem-solving led to a formula for the estimation of free testosterone in serum, which has not been improved upon to date and is still in use worldwide. He contributed to enhancing our understanding of the role that male sex hormones may play in a variety of clinical problems in endocrinology, including bone health, type 2 diabetes, and, especially, endocrine function in aging males. Alex Vermeulen literally was “a giant in endocrinology”. Beyond his scientific contributions, Vermeulen was a wise and engaging mentor, a Renaissance man, and an aficionado of the finer things in life. He owned an eclectic choice of modern artworks, all of which he bequeathed to the Ghent Museum of Fine Arts, thus significantly enhancing the museum’s art patrimony.