Alzheimer’s disease, an irreversible form of dementia, is considered the world’s most common neurodegenerative disease. The prime risk factor for Alzheimer’s is age, although it remains unclear why. It is known that the insulating layer around nerve cells in the brain, named myelin, degenerates with age. Researchers at the Max Planck Institute (MPI) for Multidisciplinary Sciences in Göttingen have now shown that such defective myelin actively promotes disease-related changes in Alzheimer’s. Slowing down age-related myelin damage could open up new ways to prevent the disease or delay its progression in the future.