One of the major beauty trends to come out of South Korea recently is the sheet mask. These are non-woven fabric masks that are soaked in a water-based lotion or serum, and packaged in single use packets that can be bought individually or in box sets. There are masks for the face, hands, feet and for specific parts of the face and body, such as under-eye masks and finger masks.
Sheet masks are applied to skin and left on for anywhere between 10 to 30 minutes, depending on the type of mask. The serums and lotions that are used to saturate the sheet masks are typically water-based solutions containing high concentration of glycerin, polyalcohols and glycols, which help to keep the sheet from drying out too quickly once it is applied to the skin. The overall effect is to saturate the outermost layers of skin with the lotion/serum; the water content gives a temporary plumped-up and hydrated appearance to the skin. Sadly, this effect is usually temporary as the water eventually evaporates and the humectants wear off. As with any type of moisturizer, the long-term efficacy of these masks is dependent upon the presence of ingredients that are known to be effective moisturizing agents, such as the natural moisturizing factors (e.g. hyaluronic acid, sodium PCA, sodium lactate), and active ingredients that are known to be beneficial to skin appearance.
Because the sheet mask swells the outermost layer of the skin, it temporarily disrupts the barrier function of the skin. This means that if used for too long, or too often, the skin might get dried out, and possibly irritated. For people who have sensitive skin or have chronic skin conditions such as eczema, these sheet masks can make skin more sensitive to irritation, particularly if the lotion/serum contains fragrance.
The bigger question about these sheet masks is the environmental cost. Similar to other single-use items like coffee pods, sheet masks are basically a convenience item which generate an enormous amount of waste. Each sheet comes in a plastic or plastic–coated foil envelope, none of which is biodegradeable. Most sheet masks are made from cotton or wood pulp, which are biodegradeable, but some are made from polyethylene or polypropylene, which are non-biodegradable. In addition, most masks are placed on a plastic film backing which is non-biodegradeable.
Sheet masks are a fun way to pamper yourself at home, but they come with an extremely high environmental cost, In the long term, a good facial moisturizer is probably a better bet.