IL-6 (Interleukin-6)

What it is

IL-6 is a pleiotropic cytokine produced by immune cells, adipocytes, muscle cells (during exercise), and senescent cells. It drives the acute- phase response (including hsCRP production by the liver) and modulates immune cell differentiation.

Why it matters

Persistent elevation of IL-6 is one of the most consistent age-related biomarker changes (“inflammaging”). Elevated IL-6 predicts:

• Cardiovascular events.
• Frailty and sarcopenia.
• Cancer incidence in some sites.
• Cognitive decline.
• All-cause mortality.

The exercise paradox

Acutely during exercise, IL-6 from contracting muscle (“myokine IL-6”) has anti-inflammatory and metabolic-signalling roles — opposite to the chronic, low-grade IL-6 produced by adipose tissue and senescent cells. Same molecule, different context.

What lowers chronic IL-6

• Weight loss (especially visceral fat).
• Exercise (training adaptation reduces baseline IL-6).
• Mediterranean diet and omega-3 intake.
• Smoking cessation.
• Pharmacology: statins, GLP-1 agonists, colchicine, IL-6 receptor blockade (tocilizumab, sarilumab) in autoimmune disease.

Related entries

hsCRP, Chronic inflammation, NF-κB.