Alum stone has (almost) only advantages. Its (almost) only drawback is that it contains aluminum salts which would be harmful to health, but the question is still not resolved.

Don’t look on a geography map. Alun is no more a city or a region than Pyrrhea is a man. The word alum comes from the Greek “als” or “aléos”, which means salt or from the Latin “alumen” which in Latin means bitter salt.

Alum stone is a mineral composed of two sulphates that is to say of two salts: potassium sulphate and aluminum sulphate. The angry word is launched. Are the aluminum salts it contains useful or harmful to health? Because indeed, the stone of alum is already quoted in the book of Dioscorides, Greek doctor born in the years 30 AD (De Materia Medica) for its astringent medical virtues (an astringent has the property of tightening the tissues and of them. dry) in particular. But since Antiquity, and in the Middle Ages, it has been used in many fields:

• by dyers, to improve the quality of fabric dyeing (alum is used as a mordant, now replaced by salt);
• by the builders, to ensure lasting protection of the living wood (alum and milk are added to the lime to coat the wood);
• by tanners, to promote the coagulation of proteins (hemostatic property) during leather work by “agro-food” (drying fish in cod canneries, transformation of muddy water into drinking water (alum takes in traps impurities giving precipitates which are easy to remove));
• by “healers” of all stripes in the fields of witchcraft, possession and the evil eye.
• very incidentally to recover her virginity.

The alum stone came from Syria, Yemen, Persia, Italy (Mont de la Tolfa) but it now comes mainly from Asia.

It is the “stone of a thousand virtues”.

It is marketed in several forms:

• The most classic is in the form of a pebble, raw, weighing 70 to 240g;
• It can be polished: block like an ingot, very slippery;
• Another ideal shape for travel: polished cylinder sold in a case;
• There is also a powder: like a talcum powder to sprinkle on the armpits, the feet but also in the shoes or the socks;
• Finally, it is available as a spray: practical and discreet packaging, slipped into your pocket or handbag for the “touch-ups” sometimes necessary during the day.

Here are our tips for using Alum stone:

• It is necessary to start by moistening the alum stone (raw or polished) by passing it under cold water;
• Then rub it on the armpits (under the arms);
• A thin layer of salt is then deposited on the skin;
• This layer of salt limits sweating and fights bacteria responsible for bad odors;
• It is the armpits that are most often affected but the face is the second favorite object of the stone, in particular after shaving;
• Rinse as for a roll-on deodorant;
• Consider this object as a personal hygiene product (like a toothbrush);
• Do not drop it: it is very fragile and breaks automatically.

The stone with a thousand virtues is:

• economical, it can be used for several years for what is for example a stone of 240g;
• ecological, it is 100% natural, sold without packaging, without gas (whereas most deodorants are presented in a spray bottle);
• effective, its action lasts several hours and sometimes 24 hours;
• very well tolerated except when ammonium salts are added to aluminum salts, the product is called “ammonium-alum” and allergic risks are inherent in the use of ammonium. This form is used in cases of “razor burn”. It prevents the formation of small buttons, stops small bleeding and calms the post-shaving period.

The first disadvantage of this product is that it clogs the sweat ducts and that limiting sweating (its reason for being) is not recommended. Sweating is a natural mechanism: the body gets rid of all the toxins produced day and night through sweat.

But that’s not the most important criticism:

• in 2009, an animal model (in vitro) led to the conclusion that aluminum salts cause tumors in mice (it should be noted in passing that animal experiments in cosmetology are currently prohibited);
• in 2011, the ANSM (national drug safety agency) declared that no link existed between the cutaneous use of alum stone and its aluminum salts and the appearance of cancer provided that their concentration is less than 0,6%;
• in 2014, the CSSC (European scientific committee for consumer safety) declared that “for lack of adequate data, the risks of the use of aluminum salts cannot be assessed”.

Regarding cosmetic products, in whatever form they are presented, aluminum salts may not exceed the concentration of 0,6% of their composition.

The European Commission (CSSC) is continuing to investigate this thorny problem, which is therefore only in the process of being resolved.

With the “thousand virtues” of alum stone, it is prudent to add a sharp, carefully read the instructions for aluminum salts and patiently await the opinions of European experts.