Biological Age
An estimate of how old the body appears biologically, based on measurable markers, as opposed to chronological age, which simply counts years since birth.
Biological age attempts to answer a different question than chronological age: not how many years have passed, but how much biological wear and function those years produced. It is typically estimated from blood markers, epigenetic (DNA methylation) clocks, or a combination of functional tests.
Two people born the same year can have meaningfully different biological ages depending on genetics, lifestyle, disease history, and other factors. That gap is what makes biological age useful as a research signal for disease risk and intervention response.
Worth Knowing
Biological age estimates vary by the test and model used. A result from one company's test is not directly comparable to another's, and a single test result should be read as a research-grade estimate, not a medical diagnosis.