Scientists at Tufts have created a powerful 3D model of nasal tissue that reveals surprising new insights into how our sense of smell regenerates and why it sometimes fades. Contrary to past assumptions, a supposedly inactive type of stem cell called HBCs may be key to repairing damaged smell neurons. These cells appear to support the birth of new sensory neurons, and their decline with age could help explain why older adults often lose their sense of smell. The model is easy and affordable to replicate, opening the door for global research into smell loss tied to COVID-19, aging, or diseases like Parkinson s.