ALL GUIDES / BIOMARKERS & DIAGNOSTICS
Understand what a measurement can tell you, what it cannot establish, and which questions to bring to primary care before adding tests.
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Start with the decision, then consider the test
- Understand biological age
Separate age estimates from everyday health and function.
- Ask whether a test changes a decision
Explore testing limits before adding measurements.
- Organize the information you already have
Use the free Starter Kit to prepare questions.
Explore the full collection
Biological Age After 45: What It Means and What to Track
Separate biological-age estimates from actionable information about your health.
Advanced Biomarker Tests After 45: What’s Worth Tracking?
Ask whether an additional test would change a decision about your care.
Epigenetic Clocks After 45: What Biological Age Tests Can and Can’t Tell You
Understand the limits of DNA-based aging scores before interpreting a result.
Continuous Glucose Monitors After 45: What to Know Before You Try One
Consider what glucose monitoring can add, and what questions need clinical context.
Assessing a longevity claim? Read the evidence behind NAD+ supplements and how to evaluate longevity experts.
Browse all guides · How we handle evidence
Educational content. Not medical advice.
Keep one next step visible: After choosing a question you want to bring to your clinician, use the weekly habit planner to write down the action or question and when you will return to it. Recording a plan does not measure a health benefit or replace clinical advice.
Put measurements in context: Browse the aging and longevity science archive and the science and research collection. The separate biohacking archive and supplements collection gather related claims to read critically; appearing in a collection is not a recommendation to try an intervention.