The use of biological age calculators in clinical practice

Biological age (BA) is defined as an integrative indicator reflecting the degree of organismal aging and biological wear of physiological systems. In contrast to chronological age, BA is a potentially modifiable variable and may serve as a biomarker of geroprotective intervention efficacy. Recent advances have enabled the development ofBA calculators based onclinical and laboratory data, epigenetic modifications, immune signatures, microbiome, and multi-omics profiles. This article reviews various approaches to BA assessment, including epigenetic clocks (Horvath, GrimAge), phenotypic indices (PhenoAge, frailty index), immune aging models (iAge), and calculators derived from standard blood tests. The present review was prepared by conducting a comprehensive literature search utilising the PubMed and Scopus databases. A comprehensive search was conducted of original and review papers published primarily between 2010 and 2024, the focus of which was the description of BA estimation methods, their predictive utility, and clinical applicability. The review discusses the potential for integrating BA assessment into clinical practice and personalised medicine, as well as the need for further validation and standardisation of these tools across populations.