Every number in Eumaia is grounded in published research — not wellness trends. Here's exactly how we calculate biological age, which studies we rely on, and what our limitations are.
Eumaia's biological age estimate is based on the PhenoAge algorithm, developed by Dr. Morgan Levine and colleagues at Yale School of Medicine and published in Aging (2018). The algorithm was trained and validated on over 11,000 participants from the National Health and Nutrition Examination Survey (NHANES III).
PhenoAge outperforms chronological age at predicting all-cause mortality, cancer incidence, disability, and multi-morbidity — making it one of the most clinically validated biological age clocks available from standard blood tests.
Primary Citation
Levine, M.E., Lu, A.T., Quach, A., et al. (2018). "An epigenetic biomarker of aging for lifespan and healthspan." Aging, 10(4), 573–591. doi:10.18632/aging.101414
PhenoAge uses nine routine blood markers — all available from a standard metabolic panel and CBC — weighted by their contribution to biological aging:
Albumin (g/dL)
Liver function, nutritional status, longevity predictor. Declines with inflammation and poor nutrition.
Optimal range
> 4.4
Creatinine (mg/dL)
Kidney filtration efficiency. Elevated levels indicate declining renal function.
Optimal range
0.7–1.0
Fasting Glucose (mg/dL)
Metabolic health and insulin sensitivity. Chronic elevation accelerates cellular aging.
Optimal range
< 85
C-Reactive Protein (CRP) (mg/L)
Systemic inflammation — the #1 driver of accelerated biological aging across all systems.
Optimal range
< 0.5
Lymphocyte % (%)
Immune competence. Low levels predict infection risk and immune senescence.
Optimal range
25–40%
MCV (fL)
Red blood cell size. Elevated MCV indicates B12/folate deficiency or liver stress.
Optimal range
80–95
RDW (%)
Red cell variation width — a powerful, underappreciated marker of oxidative stress and inflammation.
Optimal range
< 12.5
Alkaline Phosphatase (ALP) (U/L)
Liver and bone health marker. Elevations linked to liver inflammation and accelerated aging.
Optimal range
< 80
White Blood Cell Count (K/μL)
Total immune activation. Chronically elevated WBC reflects systemic immune stress.
Optimal range
4–7
The PhenoAge calculation involves two steps:
Step 1 — Phenotypic Mortality Score
The nine biomarkers are combined using a linear equation with coefficients derived from Cox proportional hazards regression on the NHANES dataset. This produces a "mortality score" that represents 10-year mortality risk better than chronological age alone.
Step 2 — Convert to Biological Age
The mortality score is converted to an age equivalent using a Gompertz survival model — mapping the predicted mortality risk to the chronological age at which the average person would carry that same risk.
Results are clamped between 18 and 100 to avoid extrapolation artifacts. All coefficients are taken directly from the published paper and have not been modified.
NHANES participants used in training and validation
Average biological age improvement seen in lifestyle interventions (Fitzgerald et al., 2021)
Statistical significance of PhenoAge vs chronological age in predicting all-cause mortality
Body systems tracked: metabolic, immune, inflammatory, hepatic, renal, cardiovascular
Additional Supporting Research
Eumaia's recommendations are informed by the published research of leading longevity scientists. These experts have not directly endorsed or partnered with Eumaia — we reference their public research and peer-reviewed publications.
Dr. Morgan Levine
PhenoAge, Biological Clocks
Yale → Altos Labs
Dr. David Sinclair
NAD+, Sirtuins, Epigenetics
Harvard Medical School
Dr. Valter Longo
Fasting Mimicking Diet, Longevity
USC Longevity Institute
Dr. Rhonda Patrick
Micronutrients, Sauna, Inflammation
FoundMyFitness
Dr. Iñigo San Millán
Zone 2, VO2 Max, Mitochondria
CU Anschutz
Dr. Matthew Walker
Sleep Science, REM, Circadian
UC Berkeley
Dr. Peter Attia
Longevity Medicine, Performance
Early Medical
Dr. Ben Bikman
Insulin Resistance, Metabolism
Brigham Young University
Dr. Eric Berg
Metabolic Health, Keto Protocols
Berg Institute
* Expert names and research are referenced for educational attribution only. No endorsement implied.
We believe in transparency. Here's what Eumaia cannot do:
Medical Disclaimer
Eumaia is a longevity education and tracking platform. Content is for informational purposes only and does not constitute medical advice, diagnosis, or treatment. Always consult a qualified physician or licensed healthcare provider before making decisions about your health. The PhenoAge algorithm and all referenced research are used for educational purposes — Eumaia is not affiliated with Yale University, the NHANES program, or any referenced researcher.
Use the free calculator — no account required.