Skip to content
Body System

Immune

Defense, inflammation, and resilience to illness.

Last reviewed
July 2026
Version
1.0
Review cadence
Annually

Overview

The immune system defends against infection and injury and regulates inflammation. Well-calibrated immunity protects; chronic low-grade inflammation, by contrast, contributes to many age-related diseases.

Why it matters

Immune resilience shapes vulnerability to infection and, through chronic inflammation, cardiovascular and metabolic disease. Much of what supports it is foundational — sleep, activity, nutrition, and vaccination.

Start Here

New to this? Read these first

  1. FoundationHealthy AgingThe best place to understand what genuinely preserves healthspan.
  2. ConditionRespiratory InfectionsColds and flu — and the antibiotics that do nothing for either
  3. BiomarkerHigh-Sensitivity CRPA marker of low-grade inflammation
  4. Signal RecordVitamin CIt doesn't prevent colds — and it isn't useless either
  5. Body SystemDigestive
Typical Journey

How this usually unfolds

  1. Understand the system
  2. Know the key biomarkers
  3. Learn the common conditions
  4. Apply evidence-based interventions

An orientation to how this topic is typically approached — not medical advice.

Major functions

  • Defense against pathogens
  • Inflammation and tissue repair
  • Immune memory (vaccination)
  • Surveillance against abnormal cells

Common conditions

Evidence-based

Prevention

  • Stay up to date on vaccines
  • Sleep and manage stress
  • Correct nutrient deficiencies
  • Maintain metabolic health
Evidence-based

Improvement strategies

  • Address chronic inflammation's causes
  • Correct vitamin D deficiency where present
  • Exercise and weight management
Explore

Explore this system across BioSignal

Related peptide families

Related lifestyle interventions

  • Sufficient sleep
  • Regular moderate exercise
  • Nutrient-adequate diet
  • Not smoking
  • Vaccination

Related diagnostics

  • hs-CRP (inflammation)
  • Vitamin D (deficiency)
  • Ferritin (context)
  • (Immune panels — clinician-directed)

Frequently asked questions

Can supplements 'boost' my immune system?

Correcting a genuine deficiency (like vitamin D when low) helps, but 'boosting' a healthy immune system with supplements has little strong evidence. Sleep, activity, and vaccination do more.

Is inflammation always bad?

No — acute inflammation is essential for healing and defense. It's chronic, low-grade inflammation that's linked to disease.

Educational information — not medical advice

Body System hubs orient you across the evidence; they don't diagnose or treat. Interpret your own health with a qualified clinician. See our Medical Disclaimer.

Is this hub clear, useful, and well-connected? Your feedback shapes what we review next.

Give feedback