The Longevity Hierarchy That Actually Matters
The practical version, before the mechanisms
If you want the practical version before the underlying science, this is it. Everything here is explained and cited properly in the sections that follow.
| Tier | What's in it | Evidence strength |
|---|---|---|
| Tier 1 — Do this | VO2 max training, resistance training, blood pressure control, not smoking, consistent sleep, healthy body composition | Strong — large cohort and trial evidence, covered in depth in the Exercise, Heart & Metabolic Health, and Sleep guides |
| Tier 2 — Reasonable, well-studied | Caloric restriction principles, time-restricted eating, a Mediterranean-style diet | Moderate-strong — genuine human trial data, covered in Sections 5–6 |
| Tier 3 — Emerging, incomplete evidence | NAD+ precursors (NMN/NR), metformin, rapamycin | Mechanistically plausible, backed by animal or observational data; human longevity outcomes remain unproven |
| Tier 4 — Proceed with real caution | Unregulated peptides (BPC-157, TB-500) and similar compounds | Little to no robust human trial data; physician guidance essential if used at all |