In order to clarify the causes of armpit odor, let’s start with a little bit of knowledge about sweat glands: there are two types of sweat glands in the human body: the large sweat glands and the small sweat glands. These are the names of the two types of sweat glands, not just their size. While the small sweat glands are distributed throughout the body (including the armpits), the large sweat glands are only distributed in the armpits, the external auditory canal, the areola, the vulva and other parts of the body, and its secretion function is relatively strong and regulated by sex hormones (which is why the onset of puberty), only the large sweat glands are the culprits of the cause of armpit odor. Everyone has sweat glands, so why do some people have armpit odor and others don’t? After years of research, this question has been basically clarified. The problem lies in the genes, armpit odor is essentially a genetic disease. We know that the human body has a total of 23 pairs of chromosomes, the problem lies in the long arm of the 16th pair of chromosomes on a gene, a small variation of this gene led to the production of a protein called MRP8 coded structural variations, and the end result is the secretion of the human sweat glands is unusually strong, the ordinary people can not secrete some of the macromolecules of the organic matter (mainly polysaccharides, the details of I won’t go into the details) were secreted. The bacteria on the surface of the body get these nutritious macromolecules, and reproduce and decompose them, producing a lot of substances with a special irritating odor. To summarize: genetic mutation – protein abnormality – sweat glands secrete abnormal organic matter – bacteria decompose and emit odor.