Complement C3 / C4

Advanced wellness

also c3, c4 complement proteins

What it isTwo central proteins of the complement cascade, an ancient arm of the immune system that opsonizes pathogens and triggers inflammation. Both are produced by the liver and behave as acute-phase reactants, rising with inflammation and consumed during active immune-complex disease.

DoesC3 and C4 levels track complement consumption in immune complex-mediated disease and overall inflammatory activity.

GoodMid-normal C3 and C4 reflect intact complement without active immune-complex disease.

BadLow levels suggest active autoimmune disease (lupus flare, immune complex glomerulonephritis, cryoglobulinemia, hereditary angioedema for C4). Persistently high levels reflect chronic inflammation or acute-phase response.

Standard

C3 90–180 mg/dL; C4 10–40 mg/dL.

Optimal

C3 110–150 mg/dL, C4 18–30 mg/dL (narrow target)

Modifiers

Falsely low if sample handling delays cause in-vitro consumption; estrogen and pregnancy raise levels modestly.

How to optimize

Lifestyle: Stress reduction, adequate sleep, avoiding overtraining all modulate complement activity in autoimmune disease.
Diet: Mediterranean and anti-inflammatory dietary patterns lower chronic complement activation.
Supplements: Omega-3 EPA+DHA 2–4 g/day, vitamin D3 if deficient, curcumin 500 mg twice daily.
Peptides: Thymosin Alpha-1, BPC-157 in autoimmune contexts.
Drugs: Disease-specific immunosuppression; eculizumab and other complement inhibitors for specific complement-driven diseases. --

within Allergy & Immune