Pullulan

What it is

Pullulan is a starch-derived polysaccharide produced by fermenting the fungus Aureobasidium pullulans, and it is also used to make edible films and breath strips. On skin it dries into a clear, flexible film that contracts slightly, which is where the short-lived "instant lifting" or "tightening" sensation in some masks comes from. It is also used to build viscosity and to hold peel-off masks together.

What it does well

• Creates a temporary smoothing and tightening effect

  The tightening is a physical film effect that lasts as long as the film does and washes off with it. There is no evidence of any lasting change to the skin, and the ingredient is not marketed by suppliers as doing more than this.

  Limited evidence

Worth knowing

• The lifting effect is entirely cosmetic and temporary

  Once the film is removed or rehydrated, the effect goes. Products sold on an "instant facelift" premise are describing a film, not a change to skin structure.

  Matters most toAnyone buying an "instant lift" mask expecting the result to persist.

Where the EU stands