Know your numbers
Measure the trend, not the snapshot.
Biological age and biomarkers turn longevity from guesswork into feedback.
Featured partner
Rythm Health
An at-home monthly blood test that tracks the biomarkers that matter, so you can see whether a protocol is actually working.
Biomarkers
What to test, and why.
Cardiovascular
ApoB
Direct count of artery-clogging particles. Arguably the best single lipid marker.
Metabolic
HbA1c
Average blood sugar over ~3 months.
Metabolic
Fasting insulin
Catches insulin resistance years before glucose rises.
Inflammation
hs-CRP
Low-grade systemic inflammation linked to heart disease and aging.
Hormone
Testosterone
Total and unbound (bioavailable) T for energy, libido, muscle — and context for TRT.
Hair
DHT
The androgen behind pattern hair loss; useful when on 5-ARIs or TRT.
Hair / energy
Ferritin
Low iron stores are a common, fixable cause of shedding.
Bone / immune
Vitamin D
Widespread deficiency; easy to correct.
Hormone
Thyroid (TSH, FT4, FT3)
Thyroid dysfunction drives fatigue, weight change and diffuse hair loss.
Biological age
What 'biological age' tests actually measure.
Epigenetic clocks (DNA methylation) and blood-based composite scores estimate how fast you're aging relative to your calendar age. They are useful for trends, but individual results vary between labs and should not drive treatment decisions alone.