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Evidence Standards

Three tiers.
Visible on every recommendation.

Every protocol you receive at Signal carries its evidence tier. Tier governs sequencing: Tier 1 first, always; Tier 3 last, rarely, and only with explicit consent.

The Framework

Tier 1 · Validated

Multiple randomised controlled trials, meta-analyses, or large-cohort longitudinal data with consistent outcomes. The intervention is defensible against the strongest skeptic.

  • ApoB-lowering therapy
  • Resistance training prescription
  • Cardio-respiratory base building
Tier 2 · Supported

Smaller trials, strong mechanistic rationale, and convergent observational data. We recommend with explicit acknowledgement of remaining uncertainty.

  • Specific micronutrient repletion
  • Sleep-architecture interventions
  • Targeted hormone support (in-scope)
Tier 3 · Provisional

Mechanistic plausibility with limited human data. Considered only after Tier 1 and 2 levers are saturated, with informed consent and a defined re-evaluation horizon.

  • Emerging biomarker-guided protocols
  • Investigational adjuncts under monitoring

On omission

What we will not prescribe is part of the standard. The absence of a recommendation is itself a recommendation.