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Ask the researchers

Ask the researchers

How do skin moisturizers work? Does it also help to wet the skin to moisturize it? (Claudia Chow, via e-mail)

Daniel BuenoMoisturizers create a “film” over the skin to prevent the epidermis (the external layer) from losing water thanks to blocking components with oily or oil-free (silicone) substances. Moisturizers also moisten the skin. Water-attracting substances such as glycerin and sorbitol keep the skin moisturized for longer. This effect can be reinforced when the formula contains substances with natural moistening compounds, such as urea and ammonium lactate, which replace missing components or enhance existing ones.

Emollient creams also contain oily compounds and non-fat lipids that bind the cells of the stratum corneum, the outermost layer of the epidermis, to moisturize the skin. This prevents skin dryness and flakiness. Other moisturizers may contain nano compounds, which are more efficient, because the active nano-encapsulated substances become more stable, interact with the skin to a greater extent and are released gradually.

Water on the skin moisturizes it for a few seconds until it dries up. Thermal water is an exception, because it has a higher concentration of minerals (such as zinc and silicate ions) than ordinary water. These ions help retain the water content inside and outside the skin cells, thus holding the moisture in.

Maria Vitória Lopes Badra Bentley
University of São Paulo (USP)