In order to slow aging, it’s important to know how circulating biomarkers change during aging, and how these biomarkers are associated with risk of death for all causes. In this video, I discuss blood test data for the oldest old, including centenarians (100 – 104y), semi-centenarians (105 – 109y), and […]

Measurement of biological age with Levine’s Phenotypic Age calculator is strongly correlated with chronological age (r=0.94; see In 2019, I measured all 9 of its analytes 3 times, with biological age readings of 35.39y, 35.58y, and 31.3y, for an average 2019 biological age of 34.09y (see That’s 12 […]

Creatinine is one of the 9 blood test variables included on the biological age calculator, Phenotypic Age ( The reference range for women and men is 0.5 – 1.1, and 0.6 – 1.2 mg/dL respectively, but within that range, what’s optimal for health and longevity? To answer that question, it’s […]