The Interstitium: What It Might Mean for Skin Gut-Skin Axis · Hyaluronic Acid · Inflammation · Interstitium · Skin Explained · Skin Science · Sep 16, 2026 by Cora Nelson Scientists are studying the interstitium, a fluid-filled tissue network beneath the skin and around the organs. Cora explains what it is, what it might teach us about skin, and what it does not prove about acne.