By Dr. Kris G McGrath MD
The underarm (axillae) is a very unique, complex, and delicate environment. The axillae consist of skin, hair and 2 main types of liquid secreting glands which form the underarm sweat. One set of glands puts out liquid of water like consistency while the other set of glands puts out, a thicker liquid, containing fatty acids and a chemical know as a pheromone. Naturally, if all is left well and good, sweating helps cool the body, and in animals pheromones help attract the opposite sex. The reason women in college sororities begin having their periods on the same day is due to their underarm pheromones. This is a powerful biological messenger, despite research downplaying it as an evolutionary left over useless biological messenger.
Of course what you want to know is where the smell comes from. The odor, more correctly, malodor, is from 2 sources. The ecrine sweat glands that produce the water like consistency have no odor. The odors are from the odor free fatty acids secreted by the apocrine glands. These fatty acids are converted to other fatty acids by underarm bacteria. These fatty acids have odor as well as the underarm bacteria.
The natural, unadulterated, underarm environment is not acidic due to sweating. When underarm products are used, such as antiperspirants, sweating is reduced, creating an acid environment. The breakdown of fatty acids by bacteria also adds to the acid environment. This is similar to acid rain. Acid rain releases aluminum from rocks and soil. This unleashes the dangerous form of aluminum into rivers, lakes, and streams causing disease in plants and water life. Antiperspirants contain aluminum salts. An underarm acid rain is produced potentially releasing the dangerous form of aluminum which has been shown to affect DNA, RNA, messenger RNA and histones, all which is an avenue to cancer.
Antiperspirants are used for sweat reduction and to a lesser degree to reduce odor, while deodorants or used for malodor, these 2 ingredients are oftened combined in underarm products.
Just under the skin of the underarms lies the lymphatic system which collects excess fluid from surrounding cells, returning it to the circulation. More importantly the lymphatic system is part of the immune system fighting off infection, disease and removes foreign particles. Interesting the lymphatic flow in the underarms and breast is bi-directional (a 2 way street), not one way controlled by valves as in other parts of the body. So chemicals applied to one underarm could expose the nearest as well as the farthest breast.
The desire for an underarm product prevails and these hygiene habits begin by age 9 or 10! So, take care of your underarms and breasts, just like your teeth, skin, heart, lungs, liver, kidneys and brain.