Inflammation Biomarkers: What Your Lab Work Is Actually Telling You
Chronic low-grade inflammation drives nearly every major disease of aging. These are the biomarkers that measure it, what the numbers mean, and what to do about them.
Inflammation is the immune system's first response to injury, infection, and cellular stress — a necessary and life-saving mechanism in its acute form. The problem is chronic, low-grade systemic inflammation: a persistent, below-the-threshold-of-symptoms activation of the immune system that silently damages tissues over years and decades. Cardiometabolic disease, neurodegeneration, cancer, and accelerated aging all share chronic inflammation as a central mechanism.
The good news: inflammation is measurable. Understanding these biomarkers gives you a window into one of the most important drivers of long-term health.
High-Sensitivity CRP (hs-CRP)
C-reactive protein is produced by the liver in response to inflammatory cytokines (primarily IL-6). Standard CRP tests detect major inflammation; high-sensitivity CRP (hs-CRP) detects the subtler chronic inflammation relevant to cardiovascular and metabolic risk.
Reference ranges:
- < 1.0 mg/L: Low risk
- 1.0–3.0 mg/L: Average risk
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3.0 mg/L: High risk
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10 mg/L: Acute inflammation (infection, injury — retest after resolution)
hs-CRP is one of the strongest predictors of cardiovascular events — arguably better than LDL cholesterol alone. The JUPITER trial showed that people with elevated hs-CRP but normal LDL had significantly elevated cardiovascular risk, and treating them reduced events. It also correlates with insulin resistance, sleep quality, adipose tissue inflammation, and cognitive decline risk.
What moves hs-CRP: Exercise (acute exercise raises it; chronic training lowers it), omega-3 fatty acids, weight loss (visceral fat is a major driver), sleep quality, alcohol reduction, and dietary pattern (Mediterranean diet is the most studied for CRP reduction).
Interleukin-6 (IL-6)
IL-6 is a cytokine — a signaling protein — that both drives CRP production and acts as a direct inflammatory mediator. Chronically elevated IL-6 is associated with muscle wasting (sarcopenia), insulin resistance, depression, and cancer progression.
IL-6 is not a standard panel item but is available through specialty labs. Optimal levels are typically < 3.4 pg/mL; higher levels signal persistent immune activation.
Interestingly, IL-6 is acutely released by muscle during exercise (acting as a myokine with anti-inflammatory downstream effects) — demonstrating that context matters for interpreting any single cytokine measurement.
Ferritin
Ferritin is most commonly discussed as an iron storage marker, but it's also an acute phase reactant — it rises with inflammation. Moderately elevated ferritin (above optimal ranges but below pathological levels) often reflects chronic inflammatory load rather than iron excess.
Optimal range: 50–150 ng/mL for most adults (note: ranges vary by lab and sex) Elevated ferritin (> 200–300 ng/mL without iron overload): Consider chronic inflammation, metabolic syndrome, non-alcoholic fatty liver disease, or excess alcohol
Both iron deficiency and iron excess carry risk; ferritin in context with total iron binding capacity (TIBC) and transferrin saturation provides the full picture.
Homocysteine
Homocysteine is an amino acid produced during methionine metabolism. Elevated levels damage the vascular endothelium, promote blood clotting, and are independently associated with cardiovascular disease, stroke, and cognitive decline — including a strong association with Alzheimer's disease risk.
Optimal range: < 8 µmol/L (standard labs use < 15, but optimal is lower) Primary drivers: B vitamin deficiency (B6, B12, folate are required for homocysteine clearance), MTHFR gene variants, kidney dysfunction, hypothyroidism
Homocysteine responds extremely well to B vitamin supplementation — methylfolate, methylcobalamin (B12), and B6 typically normalize elevated levels within weeks.
Fasting Insulin and HOMA-IR
Chronic insulin resistance drives systemic inflammation through multiple mechanisms: elevated glucose causes glycation of proteins, advanced glycation end-products (AGEs) activate inflammatory receptors, and visceral fat accumulation (which follows insulin resistance) produces inflammatory cytokines continuously.
Optimal fasting insulin: < 6–8 µIU/mL (standard ranges often allow up to 25, which is far too permissive for optimization) HOMA-IR (fasting insulin × fasting glucose / 405): < 1.0 is optimal; > 2.0 suggests insulin resistance
Practical Approach
These markers tell you where you stand but don't prescribe specific interventions on their own — they require context from the full panel and your clinical picture. Actionable starting points that move multiple markers simultaneously: consistent aerobic exercise (VO2 max is one of the strongest predictors of inflammatory status), omega-3 supplementation (2–4g EPA/DHA daily), visceral fat reduction, sleep quality improvement, and Mediterranean-pattern eating.
Test, intervene, retest in 90 days. Inflammation is one of the most responsive systems in the body to lifestyle inputs.