Methodology
How We Approach Biological Age
By Rob Lake ·
5 min read
Most biological age tools produce a single number from a single input, a DNA methylation test, a wearable's proprietary algorithm, a blood panel run once. The number is precise looking and largely static. It tells you where you stood on the day of the test and very little about what to do next.
Eirloom treats biological age as a composite of three separate dimensions, measured on an ongoing basis rather than once. Biomarkers form the first: inflammatory, metabolic, hormonal, and cardiovascular markers drawn from blood work and continuous wearable data, tracked as trends rather than single readings. A single blood draw is a snapshot. A trend across quarters is a signal.
Cognitive capacity forms the second, and it's the dimension most biological age tools skip entirely. Processing speed, working memory, and decision quality under fatigue are measured directly, not inferred from physical markers alone. Physical and cognitive decline share biological roots, but they don't always move in lockstep, and treating one as a proxy for the other misses real information.
Physical functional capacity forms the third: strength, VO2 max, mobility, and recovery speed, tested against real functional demands rather than a single fitness benchmark. This is the dimension most directly connected to how capable someone actually feels day to day, and it's often the first to show improvement once a protocol is in place.
The number that results isn't a verdict. It's an output of the system, updated as the inputs change, meant to be moved deliberately rather than simply reported. A biological age of thirty seven against a chronological age of fifty seven isn't a static fact discovered once. It's the current reading of a system that gets measured and recalibrated continuously, the same system available to every Eirloom client.
A single number from a single test tells you where you were. A composite, tracked over time, tells you whether the trajectory is the one you'd choose.