Biological age reversal measurements and physical functional tests must be combined to accurately assess anti-aging treatments, according to a commentary published in Cell Metabolism by Harvard Medical School researchers including Jesse Poganik and Vadim Gladyshev. While molecular markers can indicate whether a person’s biological age score is falling, aging researchers emphasize that physical capabilities like muscle strength and memory must also be evaluated to determine if a treatment is genuinely effective.
Understanding Biological Age Versus Chronological Age
Chronological age tracks time from birth, while biological age tests examine physiological features that change over decades. According to Harvard Medical School’s Jesse Poganik in an interview with ScienceAlert, a falling score on a well-validated molecular measure shows that specific features have shifted toward patterns seen in younger people. However, Poganik cautions that biological aging remains a unidirectional process like time itself. Traveling more slowly down a road differs fundamentally from going backward along it, meaning slower aging and actual rejuvenation are distinct outcomes.
Did you know? In the two-year CALERIE trial, adults randomly assigned to reduce calorie intake showed a small slowing in the estimated pace of aging using the DunedinPACE tool, while two other measures—PhenoAge and GrimAge—detected no significant treatment-related changes.
Molecular Markers Versus Physical Function
Evaluating anti-aging treatments creates a divide between researchers focusing on molecular metrics and those prioritizing everyday physical abilities. Molecular tests can detect cellular changes before clinical symptoms appear, offering an early window for intervention. Conversely, physical functional assessments measure tangible capabilities like grip strength, hearing, and mobility. Because training can improve physical skills without altering underlying molecular aging processes, researchers increasingly argue that neither metric should be used in isolation.
Practical Checks for Verifying Rejuvenation
To establish whether a treatment actually works, Poganik outlines three practical checks for researchers to follow:
- Was the same measurement used before and after the intervention?
- Did the change persist after the treatment ended?
- Was the result reproduced using an orthogonal approach?
These criteria help eliminate statistical anomalies such as regression to the mean, where an unusually high initial reading is followed by a normal reading without any actual rejuvenation taking place. Initiatives like the XPRIZE Healthspan competition are adopting multi-faceted approaches by assessing muscle, cognitive, and immune function simultaneously to track real-world rejuvenation.
Frequently Asked Questions
What is the difference between chronological and biological age?
Chronological age measures the exact time elapsed since birth, whereas biological age estimates the physiological condition of your body based on molecular biomarkers and cellular health.
Can biological aging be reversed?
According to researchers like Jesse Poganik, aging is a unidirectional process that cannot be fully reversed, but certain interventions may slow down the aging process or shift specific molecular markers toward younger patterns.
Why do different biological age tests give different results?
Different tools—such as DunedinPACE, PhenoAge, and GrimAge—analyze distinct biological features and biomarkers, meaning their outputs can vary depending on which metrics researchers choose to measure.
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