Properties of potassium alum

Alum stone used in cosmetics is made up of potassium alum. This mineral is used for many applications not only in cosmetics but also and especially in pharmaceutics, in the food industry, and in the industry in general, for example, to purify water. These multiple applications result from the bactericidal, antiseptic, astringent, and antiviral qualities of alum.

Since the dawn of time, alum stone has been known as an aftershave, in particular, to calm down razor burn or after hair removal. In fact, in the Greek Kosmetikon fragments attributed to Cleopatra, we can see the multiple applications of alum from that ancient time. No less than 10 different cosmetic uses are mentioned, in addition to medicinal uses. More recently, alum stone has emerged as the natural alternative to traditional deodorants. It is now available in almost every shop and every country in the world as small sticks applied on the armpits after wetting.

 The main functions of potassium alum in drugs are as an astringent, antiseptic, or adjuvant agent. The astringent action is performed by the induction of coagulation in the superficial tissue layers until the formation of a crust. The formation of alum ions neutralizes the charges on plasma proteins, causing the blood to coagulate. A similar effect is observed in disinfectants where these ions react with the free organic acid and thiol groups of proteins on microbes and free proteins, resulting in protein precipitation. This action will generate the contraction of the tissue and dry up secretions. Its adjuvant properties are mainly used in the production of vaccines where the presence of this chemical enhances the immune response.

 Potassium alum is found in its dodecahydrate form that produces a very large molecule. This large molecule cannot be absorbed through the skin when this substance is included as an astringent agent in topical OTC. If ingested, the aluminum salts are rapidly solubilized in the stomach and then they can generate aluminum hydroxide or poorly absorbed basic aluminum salts.

There is no evidence of potassium alum that demonstrates any suspicious for it to be a hazard for the consumers in the currently approved levels of use.