The obvious question first, because everybody asks it: is a sleeping mask just a night cream with better marketing?
Sometimes, but the distinction is mostly about formulation and intended use rather than a hard category boundary. A sleeping mask is generally designed as a leave-on final step, while a night cream is simply a moisturiser intended for evening use. As a final layer, a sleeping mask can combine humectants and emollients with more occlusive ingredients that reduce overnight water loss and slow evaporation from the layers beneath it. Some products could reasonably fit both descriptions.
The textures reflect that. Sleeping masks tend to be gels or gel-creams rather than rich creams, because they need to sit on the surface without either soaking in or transferring onto a pillow. Well-made ones feel almost weightless and are gone by morning.
Korean brands helped popularize the sleeping-mask category internationally in the early 2000s, with Laneige becoming one of its best-known reference points. The category has since broadened well beyond a single texture or formula.
Getting it right
A sleeping mask is usually used as the final leave-on step, but follow the directions on the specific product. If it is designed to replace a moisturiser rather than sit over one, adding another layer is unnecessary.
Use the amount the manufacturer recommends. More product does not necessarily create a better seal and may simply transfer to a pillow.
Frequency varies by formula. Some sleeping masks are designed for occasional use and others for regular use, so let the directions and your skin's response decide.
Follow the morning instructions on the product. Many are simply cleansed away as part of the next routine, while some do not require a special rinse step.
Who it is not for
People who dislike occlusive textures or whose skin tends to feel congested may prefer a lighter final layer. If a product repeatedly seems to coincide with breakouts or irritation, stop using it rather than assuming the format itself is universally unsuitable.
In the cabinet
LANEIGE Water Sleeping Mask. The original, and still the reference point. Light, gel-textured, and the one to try first if you have never used the format.
Sulwhasoo Overnight Vitalizing Mask. The luxury end, and a different philosophy: herbal, richer, built around Sulwhasoo's ginseng-led approach rather than around water alone.