Biological Age vs Calendar Age: What Epigenetic Clocks Actually Measure

A study published in the journal Aging in 2018 developed a biological age calculator — called PhenoAge — using nine standard blood biomarkers and demonstrated that the gap between biological age and calendar age predicts mortality, disease risk, and physical function better than calendar age alone. Two people aged sixty-five may have biological ages of fifty-eight and seventy-three. Understanding what that difference means, and whether it is modifiable, is one of the most consequential questions in aging science. A paper published in 2018 in the journal Aging introduced a tool called PhenoAge — short for phenotypic age — built from nine standard clinical biomarkers combined with chronological age to calculate how fast or slow an individual is biologically aging relative to the population. The tool was derived from National Health and Nutrition Examination Survey data, linked to mortality outcomes, and then validated across multiple independent cohorts including European and American populations. Individuals whose PhenoAge was younger than their chronological age had substantially lower all-cause mortal --- Paper cited: An epigenetic biomarker of aging for lifespan and healthspan Authors: Levine ME, Lu AT, Quach A, Chen BH, Assimes TL, Bandinelli S, Hou L, Baccarelli AA, Stewart JD, Li Y, Whitsel EA, Wilson JG, Reiner AP, Aviv A, Lohman K, Liu Y, Ferrucci L, Horvath S Journal: Aging (Albany NY) Year: 2018 DOI: 10.18632/aging.101414 --- Subscribe for one peer-reviewed paper made practical, every Tuesday and Friday. Free guide: How to Read Your Biomarker Panel at 55+ - {{LEAD_MAGNET_URL}} --- EDUCATIONAL CONTENT - NOT MEDICAL ADVICE This video is for general educational and informational purposes only. It summarizes peer-reviewed research. It does NOT constitute: - Medical advice, diagnosis, or treatment - Recommendations to start, stop, or change any medication - Dosing instructions for supplements or interventions - A substitute for consultation with a licensed physician Before applying anything discussed: - Talk to your physician, especially if you take prescription medications (statins, metformin, blood thinners, antihypertensives, GLP-1 agonists, etc.) - Discuss interactions, contraindications, and your individual risk profile - Get baseline biomarkers before changing your regimen if relevant Specific cautions: - Intermittent fasting: not appropriate for people with diabetes (especially Type 1), history of eating disorders, pregnancy, or underweight status without medical supervision. - Strength/Zone-2 training: medical clearance recommended for cardiovascular or joint conditions before initiating new training loads. - Supplements: third-party tested products preferred; verify drug interactions. AFFILIATE DISCLOSURE (FTC compliant): Some links in the description may be affiliate links. We may earn a commission at no additional cost to you. We only feature products and tools relevant to the research discussed. AI-ASSISTED PRODUCTION: Voice narration is generated via Edge TTS (Microsoft Neural Voice). Research, scriptwriting, and review are conducted by a human editor before publication. Reviewed: 2026-09-02