<p>Two decades after its formalization, P4 medicine (predictive, preventive, personalized, participatory) remains more framework than practice. Most implementations stall at single-omics prediction and fail to close the loop across all four dimensions. In this Perspective, we argue that the P4 framework becomes actionable only when each pillar is anchored to a specific, implementable digital technology: multi-omics for prediction, artificial intelligence for prevention, digital twinning for personalization, and blockchain for participation. We propose a tiered multi-omics classification (Tier 1: genomics, measured once; Tier 2: epigenomics/proteomics, periodic; Tier 3: metabolomics/wearables, frequent) and present preliminary metabolomic aging data from 2,072 individuals identifying nine metabolites with linear age associations. We offer a computational definition of personalization requiring baseline state estimation, trajectory prediction, and counterfactual intervention simulation via stochastic digital twin engines. For the participatory pillar, we describe a blockchain architecture enabling patient-controlled data sovereignty and a health data marketplace. These four technologies form a reinforcing flywheel, where longitudinal patient participation enriches upstream data layers. We discuss validation challenges, regulatory gaps, equity concerns, and privacy risks that must be addressed before clinical deployment.</p>