Which of the following is NOT typically an ingredient in peel-off masks?

Peel-off masks are primarily designed to form a film that can be easily removed from the skin, which is typically achieved through the use of certain substances like gelatin or other similar polymers. Gelatin is a common choice due to its ability to create a solid layer that adheres to the skin and can be peeled away effectively, while charcoal is often included for its detoxifying properties, as it can help to draw out impurities. Water is frequently used as a solvent in these formulations to help blend and activate other ingredients.

Moisturizers, however, are not typically found in peel-off masks because they don’t contribute to the film-forming quality needed to create a peelable mask. Instead, moisturizers are more commonly associated with hydrating or cream-based masks that remain on the skin to provide nourishment rather than being removed after use. Therefore, their inconsistency with the function of a peel-off mask makes them the ingredient that does not belong.