Susan E. Leeman, Pioneering Neuroendocrinologist Who Unlocked Brain's Secrets, Dies at 90

We mourn the loss of Dr. Susan E. Leeman, a truly monumental figure in the world of neuroscience and neuroendocrinology, who passed away peacefully at her home in Cambridge, Massachusetts, on Tuesday, February 24, 2026. She was 90 years old. Dr. Leeman’s pioneering work, particularly her isolation and characterization of the neuropeptide Substance P, fundamentally reshaped how we understand the intricate conversations happening within our brains and bodies.

It’s really quite incredible to think about the impact of her singular dedication. Back in the early 1970s, at a time when much of neuroscience was still finding its footing, Dr. Leeman and her team at Brandeis University made a discovery that would echo through decades of research. They meticulously isolated Substance P, a peptide previously hypothesized but never truly identified. This wasn't just a scientific curiosity; it was a revelation. This tiny molecule, it turned out, played a crucial role in transmitting pain signals, regulating inflammation, and influencing mood and stress responses. Imagine, suddenly having a key to unlock so many previously mysterious biological processes!

Her career was marked by an unwavering commitment to discovery. After her seminal work at Brandeis, Dr. Leeman brought her formidable intellect to Harvard Medical School, where she served as a distinguished professor of physiology for many years. She wasn't just a brilliant researcher, you see; she was also an exceptional mentor, guiding countless students and postdocs through the challenging yet exhilarating landscape of scientific inquiry. Many of her protégés went on to become leaders in their own right, a testament to her inspiring leadership and rigorous scientific standards. Her lab was a hub of intellectual curiosity, a place where ideas were rigorously debated and hypotheses fearlessly tested.

Beyond the laboratory bench, Dr. Leeman's contributions extended to various prestigious scientific organizations. She was a member of the National Academy of Sciences and the American Academy of Arts and Sciences, and her insights were sought after globally. Indeed, her work laid much of the groundwork for modern pharmaceutical approaches to chronic pain, inflammatory diseases, and even certain psychiatric disorders. One could argue that without her meticulous efforts, our understanding of the gut-brain axis – that fascinating link between our digestive system and our emotional well-being – would be far less developed today.

While the scientific community will deeply miss her incisive mind and gentle humor, Dr. Leeman's legacy is, quite simply, indelible. She showed us how to look closer, to ask tougher questions, and to pursue answers with unwavering persistence. Her life was a vibrant testament to the power of basic research and the profound impact one dedicated individual can have on human health and knowledge. We are all, in a way, standing on the shoulders of giants like Susan E. Leeman.