Intestinal permeability is a critical mediator of systemic inflammation and metabolic disease. Validated permeability markers (lactulose:mannitol ratio, serum zonulin, fecal calprotectin) consistently improve with lactoferrin supplementation in multiple clinical populations — including IBS patients, critically ill patients, preterm neonates, and iron-deficient adults.

How do I test my intestinal permeability at home?

Serum zonulin is available through specialty labs (LabCorp, Cyrex Arrays, or Vibrant America). Request "Zonulin" or "Intestinal Permeability Panel" from your physician or directly from a direct-access lab.

Is lactulose:mannitol permeability testing available directly to consumers?

This test requires controlled oral administration of lactulose and mannitol followed by urine collection — typically physician-ordered. Some functional medicine practitioners offer it. Home-based testing kits are emerging but not yet mainstream.