ProAge (proteomic age clock)

ProAge and related proteomic-age clocks estimate biological age from the concentrations of hundreds to thousands of plasma or serum proteins measured by aptamer-based (SomaScan) or proximity-extension assay (Olink) platforms. Landmark studies by Lehallier and colleagues (2019, Nature Medicine) demonstrated that the plasma proteome changes non-linearly with age in three distinct waves, and subsequent work trained predictive models on up to ~3,000 proteins. Proteomic clocks capture post-transcriptional and secreted signals not reflected in DNA methylation, and recent analyses suggest protein-based age acceleration associates with age-related disease risk, though platform-specific protein selection means scores are not directly interchangeable across studies.