This study investigates lifetime socioeconomic health disparities through longitudinal biomarkers from the Dutch Lifelines cohort study and biobank. We construct an allostatic load index from 12 biomarkers and analyze the dynamics of health and its association with socioeconomic status (SES) over the life cycle. Our findings reveal that health risks linked to lower SES emerge early and precede chronic disease onset. Further analysis investigates the drivers of allostatic load and emphasizes health behaviors. The results highlight the need for early interventions targeting SES-related health disparities and provide new insights into the physiological pathways linking SES to long-term health outcomes.