- Armpit Odors and Sweat
- Causes: What Makes an Armpit Smelly?
- Risk Factors Associated with Underarm Odor
- Hormonal Changes
- Release of Toxins From Organs
- Poor Hygiene
- Other Comorbids
- Intake of Certain Foods
- Nutritional Deficiencies
- Treatment Modalities for Armpit Odors
- Natural Remedies for Unwanted Underarm Odors
On a recent study published by the Journal of Investigative Dermatology, it was concluded that only 2% of the population bear the gene ABCC11.
A non production of smell from the combined bacteria and sweat glands of the underarm depicts presence of this gene. Hence, with this in mind, based on the study, only 2% of the population have odorless axillae. Majority of people do have armpit odors! 
There are more people with armpit odor than those who do not.
Armpit Odor: A Type of Body Odor
Body odor, or what they medically termed as azochrotia, bromhidrosis and osmidrosis, is a condition characterized by a disagreeable smell emitted by the human body. The fetid smell is usually given off when bacteria sever and break down the proteins into acids. In the same way, armpit odor emits its unwanted smell. 
Armpit Odors and Sweat
In contrary to popular belief, the much disliked underarm stench is not due to sweat. Acting thru the process of evaporation, perspiration functions to release the water from the human body and cools it off. It also assists in excreting harmful toxins and wastes from the body. Its end product, sweat, is consists of water and salt, particularly sodium, potassium, calcium and magnesium. It is odorless and thus, unable to produce such a stinking scent. [3, 4]
Sweat does not directly cause armpit odor
Causes: What Makes an Armpit Smelly?
The unwanted smell emitted by the underarms is actually from the human skin’s bacteria. These microorganisms tend to destroy the epithelial cells in the axillae, Once damaged, it releases 3-methyl 2-hexenoic acid, the substance responsible for its futile odor. Bacteria often are inhabitants of regions with excessive sweat and moisture, thus the reason for the existing myth correlating the smell with the underarm perspiration. 
The body’s odors are also influenced by certain acids, particularly the propionic and isovaleric acids. Propionic acids are broken down by the Propionibacteria, microorganisms residing among sebaceous gland ducts, producing a scent similar to that of vinegar. Isovaleric acid, on the other hand, gives off an odor whenever digested by Staphylococcus epidermidis. 
Risk Factors Associated with Underarm Odor
Aside from bacteria, a number of other conditions are associated with the unwanted armpit scent.
Rarely, the underarms can also smell of a fish-like odor. This condition is seen among people who have trimethylaminuria. People with this illness cannot breakdown timethylamine into timethylamine oxide. The latter substance is thus excreted by means of sweat, giving off the strange aroma of decomposing fish. 
A distinct body scent is usually recognizable when a child reaches puberty, 14 to 16 years of age among girls, and 15 to 17 years old for boys. This is a result of increasing androgen hormones, which are not active until puberty. 
Alterations in hormonal levels are also very eminent during menopause. In this period, estrogen levels dip. As a reaction, the hypothalamus signals the body to increase its temperature. The body then loses water, coming in contact with bacteria, and hence, producing armpit and body odors. 
Release of Toxins From Organs
Skin, as said earlier, functions in assisting the excretion of wastes from the body. These wastes are the released toxins. Water soluble toxins exit the body through the skin. As it does, it comes in contact with bacteria along with perspiration, hence emitting the foul odor. [8, 9]
Poor hygienic practices enable growth of more bacteria in the body. As these bacteria multiply, it also enhances the production of more disliked body, or armpit, odor. 
Armpit and body odors are also associated with conditions such as obesity, hepatic disease, renal failure and diabetes. Patients with liver disease are likely to have an odor similar to ammonia, while those with renal problems tend to smell like nail polish lacquer. [2, 10]
Intake of Certain Foods
Ingestion of foods rich in spices may affect one’s smell. Garlic, curries, chives and onions may result in a momentary alteration of one’s usually normal scent. 
Being deficient in zinc may also bring about changes in the body’s natural scent. The deficiency may lead to a decreased immune system and an increased buildup of bacteria. Hence, a more likely occurrence of an unpleasant smell. 
Treatment Modalities for Armpit Odors
The following should be remembered in eliminating unwanted underarm odors: 
- Maintain cleanliness of the armpits. Wash with an antibacterial soap to decrease the resident bacteria.
- Antiperspirants and deodorants can be of use. Antiperspirants block the sweat production among glands, deodorants tend to acidify the skin even more, making it more difficult for the bacteria to thrive.
Antiperspirants and deodorants can be utilized to block sweat production and acidify the skin, preventing unwanted underarm odor.
Maintain hair-free underarms. The presence of hair reduces the evaporation of sweat, thus more bacteria reside, and more smelly underarms exist.
Shaving underarms to maintain hairless, odor-free armpits.
- Botulinum toxin, a genetically modified derivative of Clostridium botulinum, blocks the signals directed from the brain to sweat glands. This results to less perspiration and hence, decreased bacteria and smell. This is usually given as 12 injections, with each session lasting for 2 to 8 months.
- Use of natural fiber clothing can be done for better excretion of sweat.
- Avoid spicy food, such as curry and garlic.
Natural Remedies for Unwanted Underarm Odors
Certain home cure treatments can be tried on to procure relief from underarm odors.
- Baking soda, cornstarch and baby powder can be utilized to create an alkaline exterior, providing dryness and diminished odors in the armpits.
- Herbal teas such as rosemary and sage can also reduce the unlikable armpit scent.
- Bauxite crystals can also control armpit scent with efficacy.
- Topical application of concoctions and juices derived from turnips and radishes are also helpful
- Tea tree oil admixed with water has antibacterial content, thus reducing underarm odor.
- Leafy green vegetables, or even chlorophyll supplements can also help with the “smelly” problem.
- Vinegars, both the white and the apple cider kind, reduce body odor by decreasing the skin’s acidity.
- Hydrogen peroxide diluted in water may also be used as a skin rinse, and is effective against body odor.
- Magnesium, Vitamin B complex and zinc supplements also diminish one’s body odor. [10, 12]
- Sweat Mineral- Element Responses During Seven Hours of Exercise-Heat Strass. International Journal of Sports, Nutrition and Exercise Metabolism. 2007 December; 17 (6): 574-82.