Zinc oxide as a deodorant?

Antibacterial substance inhibits sweat odor-causing skin germs

Deodorants with zinc oxide could help against bad odor and small wounds under the armpits. © Anetlanda / istock
Read out

Against the Achselmief: zinc oxide helps against unpleasant odor. As confirmed by a study, the antibacterial agent inhibits the growth of odor-causing skin germs in the armpit, thus reducing the number of wet socks. At the same time, zinc oxide promotes the healing of smaller wounds, such as shaving. This could make zinc oxide deodorants a further alternative for deodorants containing the controversial ingredient aluminum.

Our armpits are a perfect habitat for bacteria. The microorganisms feel particularly well in the warm and humid environment under the arms - and provide again and again for Naserümpfen. For genera such as Corynebacterium or Staphylococcus feed on those substances that we exude in nervousness, arousal or anxiety. The degradation of these substances produces chemical compounds with a characteristic scent: the odor of sweat.

In order to tackle the unpleasant muffle, deodorant manufacturers follow three main strategies: they try to mask the odor with the help of strong perfumes, inhibit sweat gland activity with substances such as aluminum, or even attack the bacterial causative agents themselves. In this case, antimicrobial ingredients are used to inhibit the excessive proliferation of dermal germs.

Anti-odor agent

With support from Colgate-Palmolive, a well-known personal care company, researchers led by Khaled Ghathian from the Hvidovre Hospital near Copenhagen have now tested a new candidate for this purpose: zinc oxide. The chemical compound of zinc and oxygen has long been known in medicine for its antiseptic properties. It is traditionally used in skin and wound treatment and is contained in baby powder, for example.

But is the substance also suitable to kill the bacteria responsible for the smell of sweat? To find out, the research team treated 30 subjects for 13 days with zinc oxide in an oil-in-water emulsion. One armpit was supplied with the real agent, while the other was given a placebo. display

Armpits smell better

Neither the participants nor Ghathian and his colleagues even knew which armpit had received which treatment. In the course of the study, the scientists documented how bacterial growth changed and also asked the subjects for their own perception of the sweat odor. Did they notice a difference between the right and left axilla - and if so, which ones did they smell better?

The evaluation showed that zinc oxide actually reduced the subjectively perceived muffle and inhibited the growth of odoriferous microbes such as Corynebacteria and Staphylococcus hominis. The daily application of zinc oxide formulations seems to be able to effectively counteract the sensation of underarm odor.

Help with small wounds

However, a deodorant made from zinc oxide could not only be useful against undesirable odors. Further studies confirmed that the substance also helped with small wounds that the researchers had added to the subjects using a lancet or a CO2 laser. Thus, the area around the zinc oxide-treated wounds was less red and they healed faster - a handy feature, for example, after the underarm shave.

"The most common response we received from participants was, 'Where can I buy this fantastic product?'" Says co-author Magnus gren from Bispebjerg Hospital in Copenhagen. As he and his colleagues report, the manufacturer is already working on the commercialization of its zinc oxide emulsion and thus on another alternative for deodorants with the controversial ingredient aluminum. (Meeting ECCMID, 2019; abstract 1554)

Source: European Society of Clinical Microbiology and Infectious Diseases

- Daniel Albat