• Lourdes Varadé, chemical engineer

    Syndets: soapfree soaps

    7 Jan Syndets: soapfree soaps

    Nowadays we are no strangers to skin care concepts like “cleansing bars” and “dermatological bars” as the cosmetics industry has managed to develop “soapfree soaps”. We wash our hands with bars that contain no soap and our gels are “soapfree”. Soap’s day has passed: welcome to the “syndet”.


    Soap is the result of a chemical reaction (saponification) between a fatty acid and an alkaline base. If quantities are not right, the reaction produces alkali remains and a basic pH soap that is detrimental for our skin. But even a perfectly formulated and manufactured soap is distinctly alkaline in an aqueous medium.

    The fact that our skin is mildly acidic is the result of the combination of lactic acid and lactate that make up sebum (the lipid mantle). Skin has the ability to regulate pH changes and, because of this self-regulating function, occasional soap use does not affect pH. However, using soap on an ongoing basis removes oil from our skin and the resulting destruction of the lipid mantle undermines the skin’s barrier function.


    What is a syndet?

    The word “syndet” is derived from “synthetic” combined with “detergent”. Technically it refers to the binding that occurs between different detergents, also called surfactants or tensioactive agents. These detergents, which have an affinity for oils and repel water, surround dirt with small structures that are then removed by water.

    The detergents used in these gels and bars are mild anionic surfactants, used to develop high quality products. The most commonly used surfactant is Sodium Laureth Sulfate. Because anionic surfactants are potentially irritating, in formulations they are combined with other more dermocompatible surfactants. Syndets also contain suitable quantities of emulsifiers, humectants and preservatives.

    From a technical viewpoint, syndets have other advantages over soap, such as the fact that they admit the possibility of using additives (colorants and fragrances) that are not suitable for soaps.


    Soap vs. syndet

    Syndets are recommended for cleansing sensitive skin and even baby skin, as they are far more gentle and skin-friendly than traditional soaps. But remember that the anionic surfactants contained in syndets may cause sensitization problems in reactive skins. Nonetheless, even though syndets might prove to be a source of irritation for a small segment of the population, they are undoubtedly much more recommendable than traditional soaps.


    Syndets in the market

    Syndets are available in two forms in the market: as a bar or as a gel. The bars are called “cleansing bars” or “dermatological bars”. Gels are labelled as being “soapfree”. Both bars and gels in this form are “soaps without soap.”

    The vast majority of products available in the market today are syndets. Soap itself has been relegated to the traditional crafts sector – a memory of a time when cosmetics were not widely used and when people used the same soap for their bodies and their clothes.