New to biological age testing?
Start here.
The field of biological age testing is exciting, confusing, and full of overpromise. This guide walks you through the fundamentals — what the science actually says, what tests actually measure, and what questions to ask before spending money.
Understand what biological age means
Biological age is an estimate of how old your body appears based on molecular, cellular, or physiological markers — as opposed to your chronological age (years since birth). It is not a diagnosis.
Learn the basicsLearn how aging clocks work
Aging clocks are statistical models trained on biomarker data. They differ in what they measure (DNA methylation, proteins, blood biomarkers), what they predict (chronological age vs mortality risk), and how well they have been validated.
Explore clock typesKnow the limitations
A single "biological age" number hides enormous complexity. Different organs age at different rates, measurement uncertainty is rarely reported, and many commercial claims outpace the evidence. We rate everything by evidence tier.
Read our methodologyCompare tests side-by-side
We catalog every major direct-to-consumer biological age test with pricing, sample type, turnaround, evidence tier, and honest assessments of what each test can and cannot tell you.
Compare testsUnderstand what you can actually do
Some interventions have strong evidence for slowing biological aging (exercise, diet, sleep). Others are promising but unproven (metformin, rapamycin). We separate science from hype.
Explore interventionsReady to compare tests?
See every major biological age test side-by-side with pricing, evidence ratings, and honest assessments.
View comparison table