How do deodorants work?

Deodorants and antiperspirants are products that many people use on a daily basis and are often used interchangeably. However, the two terms are not interchangeable as they use completely different actives and mechanisms of action to reduce sweat and body odor.

Differences between deodorants and antiperspirants

The main difference between deodorants and antiperspirants is how they reduce body odor. To a large extent, the body odor we emit is a consequence of the metabolic activity of the bacteria that inhabit our skin, which, depending on the occasion, produce a foul-smelling combination of volatile organic compounds with volatile fatty acids and thioalcohols. main ingredients.

To solve this problem, deodorants contain antibacterial compounds such as triclosan and chlorhexidine that fight odor by directly attacking bacteria. In Europe, the maximum allowable concentration of triclosan in deodorants, face powders and other cosmetics is 0.3%, and in rinses – only 0.2%.

As for antiperspirants, they don’t work on the bacteria that produce the smelly compounds that accompany sweat. Antiperspirants contain chemical ingredients that aim to prevent or limit the production of sweat and therefore remove the raw materials used by bacteria to make us stink.

These compounds are always based on aluminum or zirconium. In particular, aluminum chlorohydrate is one of the most commonly used. They work by forming a polymer plug that, through physical blockage and chemical inhibition, prevents sweat from escaping from the sweat glands. The action of antiperspirants is not permanent, as over time the cork breaks and sweat is released.

Alcohol free and non sticky

Despite everything, deodorants and antiperspirants share some common characteristics. In both cases, they use the backbone of cyclomethicones, cyclic molecules that evaporate quickly and easily. This feature allows them to transfer deodorant or antiperspirant ingredients to the surface of the body and immediately evaporate quickly, preventing skin stickiness. Cyclopentasiloxane is a common solvent in Unilever products such as the popular Ax deodorant and antiperspirant.

In general, before the advent of cyclomethicones, it was common and still is for many products to use alcohols as solvents, but they take longer to dry and can also irritate the skin more easily.

A bit of history: from MUM to Rexona

The first deodorant brand, developed by an unknown inventor from Philadelphia, USA, was called MUM and was registered in 1888. It was a waxy cream containing zinc oxide as an active ingredient to kill odor-causing bacteria. In 1952, MUM innovated again with the introduction of the first deodorant. roll on. Today roll on it is one of the most important uses in the deodorant industry and the MUM brand continues to be active in the market.

As for the first ever commercial antiperspirant, it was called Everdry and was applied with a cotton swab. It was put on the market in 1903. A few years later, the Smell appeared (Smell, oh no!), a toilet lotion to prevent excessive sweating, developed and trademarked in 1909 by Abraham D. Murphy. Both Everdry and Odor-o-no used aluminum chloride as an active ingredient.

Odor-o-no began to grow in popularity in the summer of 1912 after it was advertised at an exhibition in Atlantic City. In 1914, Odor-o-no became Odo-ro-no for the first time. And in subsequent years, the product line diversified. The potential and popularity of the brand meant that it changed hands throughout the 20th century from different companies. Until it was bought by Unilever NV in 1986, which abandoned the Odo-ro-no brand in favor of Rexona. Although today it is the brand of deodorants and antiperspirants that the company sells in most of the countries in which it operates, the word odorono still appears on some products.

Deodorant that never leaves you

Rexona is now the world’s best-selling deodorant brand and the creator of one of the best advertising phrases in history: the famous “Rexona never leaves you” slogan. The decision took on special significance when the brand incorporated Motionsense technology into its products.

According to Unilever, the Motionsense system uses exclusive micro-capsules that are activated by the friction that occurs in the armpits when we move, causing the capsules to burst and release freshness. This allows you to extend the effect of the deodorant. How is this possible?

Well, very simply, among the ingredients of this deodorant there are especially interesting ones used as additives, which are called maltodextrins. Like other cyclodextrins, they are cyclic oligosaccharides (cyclic sugars) derived from the starch of various cereals, including corn. Some bacteria possess specific enzymes (cyclodextringlycosyltransferases) that catalyze the conversion of starch into cyclodextrins.

Maltodextrins have a hydrophobic cavity capable of accommodating hydrophobic molecules, meaning they are repelled by water. This allows them to trap and encapsulate odor molecules such as linalool, geraniol, citronellol and others that are often present in deodorants. When we apply deodorant, a couple of maltodextrin and fragrance settle on our skin, sticking to the spray area. Movement and friction break down the microcapsules that gradually release pleasant fragrances, and thus the deodorant does not leave you, because the fragrance is released gradually and thus lasts for a long time.

Raul Rivas Gonzalez, professor of microbiology at the University of Salamanca

This article was originally published on The Conversation. Read the original.

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