New research sheds light on aging dynamics and protein stability. A comprehensive proteomic analysis identified a critical inflection point at approximately 50 years of age when aging accelerates, with variable tissue-specific aging rates and key proteins implicated in cardiovascular aging. Concurrently, a large-scale study overturns the view that protein cores are highly sensitive to mutations, revealing robust stability rules and structural tolerance, facilitating accelerated protein design. These findings, published in Cell and Science respectively, refine biological aging concepts and open new paths for protein engineering in therapeutics.