17 posts
The Yale calculator is Levine's PhenoAge: a nine-biomarker mortality model fit in NHANES III and rescaled into years. Here are the coefficients, the unit traps, the noise floor, and how we would track it over time.
Epigenetic age kits report a number derived from DNA methylation at a few hundred CpG sites. Here is how that number is computed, how much of it is noise, and what to measure instead if you want something you can track.
Biological age tests run from about $75 for a blood-chemistry clock to $300-$500 for a methylation array, with outliers above $1,000. Here is what each tier measures, how reliable it is, and how to compute the same clocks yourself from raw data.
A technical guide to biological age testing: what epigenetic clocks measure, which ones to compute, how to get raw methylation data, and the failure modes that make a score move when your biology hasn't.
How to choose a DNA methylation test that computes GrimAge and DunedinPACE, what the raw array files must contain, and what moves the number.
How to choose a DNA methylation test by what data it returns, not by the clock names on the marketing page, and how to run the clocks yourself from raw IDAT files.
A direct look at blood-chemistry clocks, methylation clocks, and plasma proteins: which markers carry the signal, how to compute biological age from your own lab data, and how much of the number is noise.
A glycan age score is a regression of IgG N-glycan peak ratios onto chronological age. Covers what the assay measures and how the number is built.
A technical read on epigenetic clocks, blood-chemistry clocks, and survey-based 'bio age' calculators: what each one measures, how precise it is, and how to compute one yourself from your own data.
Three different things get called a DNA clock. This page covers the epigenetic age clock, which assay to run and how to compute the score yourself.
DNA age tests read cytosine methylation at a few hundred CpG sites and regress it onto chronological age. Here is how the assay works, which clocks are worth running, what the error bars really are, and how to process the raw data yourself.
A consumer epigenetics kit measures DNA methylation at CpG sites on an array, then feeds those values into a regression model that outputs an age-like number. Here is what the assay does, what the error bars are, and how to work with the raw IDAT files yourself.
Most online biological age calculators are quizzes. Here is what the published estimators take as input, how to compute them from your own blood panel or methylation array, and how much weight the output deserves.
Levine's PhenoAge is a nine-marker blood algorithm you can compute yourself in about twenty lines of Python. Here is the formula, the unit conversions that break it, and how it compares to the methylation clocks from the same lab.
What biological age tests measure and which clocks are worth running. Covers computing them from IDATs and a blood panel, and how much is noise.
A practical comparison of DNA methylation tests: which array, which clocks, how to get the raw IDATs, and how to process them yourself with sesame and dnaMethyAge. Plus the noise sources that make a single epigenetic age number close to meaningless.
The Sinclair-associated biological age test is a buccal DNA methylation clock. Here is what methylation clocks measure, how noisy they are, and how to get data you can analyze yourself.