Skin moisturization

Balms before the science of hydration

Long before we talk about ceramides or transepidermal water loss, skin care already seeks to soften dry surfaces and protect them. The Smithsonian collections notably show the place of balms and ointments in American homes of the 19th and early 20th centuries. These products often combine promises of care, comfort and beauty, with much broader indications than those of a current face cream.

Vaseline marks a turning point in this history: Robert Chesebrough filed his patent in 1872. This material became a common base for ointments. Its interest in hydration may seem paradoxical, since it does not provide water. Above all, it forms a film which slows down its loss. The principle remains present in modern skincare: protecting the water already in the skin can be as important as providing ingredients that retain it.

Hold water and fat together

Another difficulty is that of formulation. Water and oil tend to separate, whereas a cream must remain homogeneous and pleasant to spread. Emulsifiers help stabilize their mixture. In the history of NIVEA reported by Beiersdorf, the use of Eucerit plays a central role in the creation of the cream in 1911. This progress concerns as much the conservation and manufacturing of the product as its sensation on the skin.

The emulsion offers great freedom: you can modify the proportion of fatty substances, the texture and the ingredients dissolved in each phase. Treatments are no longer limited to a very protective balm. Lotions, creams and lighter textures may suit different preferences. This diversity does not establish a ranking from best to least good: a formula that is pleasant on oily skin may lack comfort on very dry skin.

Understand what makes the surface soft

In the middle of the 20th century, researchers took a closer interest in the water contained in the stratum corneum. In 1952, Irvin H. Blank published work on the factors that influence this water content. The question becomes more precise: beyond the greasy feel left by a product, what is happening in the surface layer of the skin? This approach opens the way to a more detailed evaluation of moisturizing care.

Research then explores the substances capable of retaining water, the lipids present between cells and the effects of washing on this balance. We now measure surface hydration and water loss, in addition to feeling. A cream can thus be studied for the duration of its effect and its influence on the skin barrier, instead of judging only its softening power at the time of application.

Take inspiration from the skin barrier

Ceramide formulas are part of this research: they seek to provide lipids close to those which naturally participate in the barrier. A trial published in 2019, conducted on the legs of 24 people with dry skin, compared a ceramide cream to a hydrophilic cream. Several measures of hydration and barrier function evolve more favorably with the first after four weeks.

Proportions, other components and use also matter. The history of moisturizers therefore results less in a miracle ingredient than in better-adapted formulas: retaining water, limiting its evaporation and making you want to repeat the procedure because the skin is more comfortable.