The key to gentle cleansing is to start with a mild product and avoid too frequent washing. The chemical structure, pH and cleansing ability are crucial for a good cleansing product, which should be individually tailored to your skin type.
The first evidence of soap production can be found in the ancient civilization of the Sumerians, who lived in the area of Sumer in southern Mesopotamia in the 3rd millennium BC. It is believed that they overlooked the purifying effect of the alkaline mixture and used it as a cure for injury. Egyptians and Greeks took over the instructions for the chemical formulation, but the purifying effect of soap was first established by the Romans(1).
In the 17th century, the French King Louis XIV helped soap reach a new heyday by bringing the best soap makers to Versailles. Four centuries later, traditional olive oil soap production continues to thrive in Marseille, as well as in many Mediterranean countries.
Soap molecules attribute their properties to the fact that they consist of a water-repellent (hydrophobic) and a water-attracting (hydrophilic) part. This is why they do not completely dissolve in water, but rather form micelles and act as surfactants.
Surfactants are substances that reduce the surface tension of a liquid or the interfacial tension between two phases and allow or support the formation of dispersions or act as a solubilizer.
However, soaps not only remove dirt, but also remove part of the natural oil film of the skin. This can lead to chapped, rough skin, especially if washed too frequently. Protection against this condition is offered by soap with a high glycerine content(2).
These so-called syndets („syn“ from synthetic and „det“ from detergents) act as a soap, but are often more skin-friendly, as their pH level has been adjusted to better suit skin.
There are a lot of factors, including chemical structure, pH, and cleansing ability that are crucial for a good cleansing product (3). The key to gentle cleansing is starting with a mild product and avoiding too frequent washing. Some products add moisturizing agents such as aloe vera, provitamin B5, and purslane, which also possess anti-inflammatory properties. (Check out the citations in our article on panthenol.)
One of the most important cosmetic preparations is the oil-in-water (O / W) emulsion, in which a lipid phase is dispersed in a water phase. Most of the creams for normal to mixed skin usually consist of this type of emulsion. Characterized by a pleasant application, they are non-greasy on the skin and are absorbed quickly.
Regarding foam cleansers, these are also formulated as oil-in-water emulsions. Nevertheless, this formula is not always suitable for dry skin as there is inadequate moisturization of the skin. In these cases, a water-in-oil (W / O) formulated oil or balm cleanser is recommended, which contains lipids in which water droplets are distributed.
An important pillar of the cosmetic treatment of seborrheic skin is the thorough, but gentle cleansing of the skin, as too aggressive cleansing measures can cause a worsening of seborrhoea.
A well-suited formulation for the care of seborrheic skin is usually the O / W emulsion. W / O emulsions and ointments should be avoided in order to prevent cosmetic-induced acne, also known as acne cosmetica (4).
Independent of the skin type, double cleansing may lead to skin barrier dysfunction due to a reduction of natural moisturizing factors. A good alternative is offered by the combination of a specific eyelid cleanser, such as a dual-phase cleanser containing a water-based and oil-based mixture (5), and a gentle foam cleanser for the rest of the face, neck, and body. The addition of natural moisturizing factors in a cleansing product is essential in order to preserve the integrity of the skin barrier.