BiogerontologyJun 18, 2025

Differences in how first- and next-generation epigenetic aging clocks work and are useful

Longevity & Aging Weekly Brief ↗PubMed ↗DOI ↗

Updated Apr 1, 2026

Abstract

Next-generation epigenetic aging clocks are associated with a greater number of health and disease signals than first-generation clocks.

Next-generation clocks are specifically trained to connect with health, lifestyle, and age-related outcomes.
Evidence suggests that these clocks are more predictive of age-related outcomes compared to first-generation models.
Next-generation clocks may respond better to interventions aimed at influencing aging.
A comprehensive review of existing literature shows that various interventions can affect at least one epigenetic aging clock.
The choice of a specific aging clock should align with the specific research application and objective.

Simplified

Aging biomarkers that predict age given methylomic data are referred to as epigenetic aging clocks. While the earliest, first-generation clocks were exclusively trained to predict chronological age, more recent next-generation models have been explicitly trained to associate with health, lifestyle, and/or age-related outcomes. Although these next-generation models have been trained using distinct approaches and techniques, existing evidence indicates that they associate with a greater number of health and disease signals than first-generation clocks. Moreover, they are often more predictive of age-related outcomes and appear more responsive to interventions. In this work, we provide definitions for first- versus next-generation clocks and discuss the potential merits of further dividing next-generation clocks into sub-categories. In addition, we summarize existing next-generation epigenetic aging clocks, including how they were trained and how they can be accessed. Given the relative value of interventional data over observational data, we comprehensively tabulate existing literature documenting the ability of an intervention to influence at least one epigenetic aging clock. While we acknowledge that the decision to a use a specific clock is ultimately dependent on the research application and goal, current evidence suggests that next-generation models should be generally prioritized for health-oriented association and interventional studies.

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Declarations. Conflict of interest: Both authors declare that they are full-time employees of the company Longevity Sciences, Inc. (dba Tally Health). The authors have no other conflicts of interest to declare.

PubMed

Differences in how first- and next-generation epigenetic aging clocks work and are useful

Abstract

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