Beta-Glucan

Schizophyllan is a beta-glucan, a branched polysaccharide produced by the fungus Schizophyllum commune, commonly known as split gill mushroom. Beta-glucans as a group come from oats, yeast and fungi, and the source affects the structure.

How it works

Two mechanisms, one straightforward and one less so.

Physically, it is a large hydrophilic molecule that holds water and forms a light film on the skin surface, reducing the rate of water loss. That much is uncontroversial.

Biologically, beta-glucans are recognised by receptors on immune cells, including dectin-1 and complement receptor 3. Beta-glucans have been studied in wound healing and in modulating inflammatory response on that basis, and it is the mechanism behind their reputation for calming irritated skin.

Structure and source

Beta-glucans differ in their branching pattern and molecular weight depending on origin, and those differences affect both how they behave on skin and how strongly they interact with those receptors. Schizophyllan has a specific triple-helix structure that has been studied in its own right, including in fields outside cosmetics.

So "beta-glucan" on an ingredient list is a category rather than a single substance. Oat beta-glucan and schizophyllan are related but not equivalent.

Penetration

Beta-glucans are large molecules, which limits how far they travel into skin. Some research suggests the smaller fractions penetrate further than molecular weight alone would predict, but the surface effects, hydration and film formation, are better established than anything happening at depth.

Why it appears with actives

Frequently formulated alongside exfoliating acids and retinoids, where the aim is to offset the barrier disruption those ingredients cause. Its hydrating and soothing properties are complementary to the active rather than competing with it.