Fragrances and Deodorants

No more embarrassment? Can Skin Microbiota Transplant Save Stubborn Underarm Odor?


Scientists have long confirmed that armpit odor comes from the metabolites of skin microbes. In the face of this trouble that plagues many people, although there are already methods such as chemical agents and laser surgery, can it be solved by applying the idea of ​​flora transplantation based on the theory of the microbiome?

Today, we focus on the generation of underarm odor and its latest micro-ecological intervention plan. We hope this article can bring some reference and inspiration to relevant industry professionals and readers.

Underarm Odor and Microorganisms
Your skin is littered with microbes, and your armpits are no exception. These warm and humid places are a paradise for bacteria. However, the microbes living in the armpits are quite rude. They stay at home and make the house stink, leaving us to deal with those odors and suffer the embarrassing consequences of those odors.

Scientists have known since the 1950s that bacteria are responsible for underarm odor. While the armpit microbiome is made up of many types of bacteria, mainly Corynebacterium and Staphylococcus, which are also the main killers of body odor. These microbes break down odorless molecules secreted by the sweat glands in the armpit, releasing foul-smelling byproducts.

The available experimental evidence explains something our noses have always known: Not everyone’s underarm odor is the same. Factors such as genetics, gender, and age have been associated with inter-individual differences in the composition of the armpit microbiome and in the production of odor. In recent years, as scientists have gained a better understanding of the microbes that produce body odor, they have come up with new strategies to manage odor by targeting odor-causing bacteria.

Factors affecting underarm odor
The chemicals that cause malodors fall into two broad categories: volatile fatty acids (VFAs) and mercaptans. VFAs are the source of acidic odors in body odor. Thiols are sulfur-containing compounds that give off a stench of varying degrees—some have a meaty onion smell, while others are fruity and less nasty. To make VFAs and thiols, bacteria use a special enzyme to process sweat molecules, which produce the nose-wrinkling odor.

The mixture of VFA and thiols caused the different odors in the human underarm, and the production of these odors is also related to the body’s genes. For example, scientists have discovered a gene that is crucial for the development of underarm odor – ABCC11. The ABCC11 gene encodes a protein that pumps odor-producing precursors to the surface of the armpit, where it is then metabolized by bacteria.

A mutant of ABCC11 blocks odor production. Interestingly, this ABCC11 mutant is more prevalent in East Asian populations than in people of European and African ancestry. These findings partly explain geographic differences in the type and severity of underarm odor in people around the world, and raise questions about body odor-related evolution.

Gender factors are also important. A study of 24 white participants showed that male participants had higher bacterial abundance and a stronger armpit odor, which is characterized by fatty and sour odors, compared to female participants. In general, women have lighter body odors, and some people have components in their body odor spectrum that correlate with the smell of cat urine.

These sex differences may be related to differences in the composition of the axillary microbiota. For example, males have more species of Corynebacterium than females, and Corynebacterium is a major producer of VFAs and thiols. However, the researchers observed gender differences in underarm odor only in participants who did not use antiperspirant. Male and female participants who used antiperspirant had similar amounts of bacteria in their armpits, as well as odor characteristics and intensity.

Age is also an important factor. A recent study of the armpit microbiome of individuals of different ages found that people aged 55 and older had more armpit bacteria and more species of Corynebacterium than those aged 18-30 and 35-50. The authors speculate that this may be related to the musty old man smell emanating from older adults, although more research is needed to determine if this is the case.

Say NO to underarm odor
Thanks to deodorants and antiperspirants, we’re not at the mercy of armpit bacteria. However, these products are not entirely effective. Although deodorants and antiperspirants can reduce the total number of bacteria in the armpit, they can make it easier for odor-producing actinomycetes to grow, which can be more stubborn than non-odor-producing bacteria, causing bacteria that are difficult to handle and control. stink.

In some cases, people take drugs that suppress sweat glands to deal with excessive sweating. Others take a more invasive approach to managing the sweat glands, permanently destroying the sweat glands with laser treatment to manage the sweat gland’s armpit microbiome.

But it doesn’t have to be that way. Based on years of research into armpit microbes and their foul-smelling byproducts, scientists are creating a new way to control underarm odor by targeting the odor-producing microbes.

Axillary microbiota transplantation, supported by scientist Christopher Callewaert, known as the armpit doctor, is one such approach. The process is simple: Antibiotics are given to people with severe underarm odor to deplete their armpit microbiome. The scientists then swab the armpits of the less-smelling donors and smear the microbes on the recipients, who leave the armpits unwashed for a week to allow the new bacteria to colonize.

All 18 patients who received transplants experienced improvement in underarm odor, and this improvement persisted for more than a month. However, this process also carries risks, which can transfer potentially pathogenic bacteria from the donor to the recipient. In conclusion, Callewaert does not believe that axillary microbiota transplantation will become the mainstream solution for underarm odor, but it may be considered in severe cases of underarm odor.

Another strategy is to use specific bacteria or compounds on the armpits to defeat or eliminate odor-producing species. There are several products on the market today that use this approach. These new deodorants have some good bacteria added to them that are more competitive than odor-producing species.

For example, scientists recently developed an underarm cream that contains live lactic acid bacteria to reduce the number of odor-forming coryneform bacteria in a subject’s armpit. Other products incorporate compounds such as acids into deodorant formulations to lower the pH of the armpits, making the environment less favorable for these bacteria.

In conclusion, a deeper understanding of the armpit microbiome and the odor it emits has important practical implications. Plus, it gives you peace of mind that underarm odor isn’t your problem, it’s the microbes.