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The Chemistry of Body Odor (BO)

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What Causes Body Odor?

Body odor is unpleasant and most of us look for ways to get rid of this bad smell. However, before trying to look for options that can help us eliminate body smell, it is important to understand what exactly causes this malodor and if it poses any risk to our health. Medically termed as bromhidrosis, osmidrosis or ozochrotia, body odor is caused when bacteria that live on the skin break down protein into certain acids.

A common misconception is that the smell given off by the body is of the bacteria itself when it is actually due to the breakdown of sweat into acid. In humans, body odor becomes evident when a person reaches puberty and is more prevalent in people who eat spicy food or are obese. This problem is common in people with certain medical conditions such as the diabetics who can have strong, repulsive body odors.

People who sweat excessively (a condition known as hyperhidrosis) may also be susceptible to body odor. But in some cases, the salt level in their sweat is too high to be broken down by bacteria and is also dependent on the type of sweat glands involved. Our feet, armpits, belly button, groin, genitals, area behind the ears and pubic hair tend to have more odor than the rest of skin.

Body odor is perceived as unpleasant by most people but this smell can be of great use to dogs and other animals who can use it to identify a person as each individual has a distinct body odor (depending on diet, age, gender and medication taken). This is the reason why sniffer dogs are deployed to search for criminals or predators. They are able to smell their prey across long distances.

Chemicals Responsible for Body Odor

When we talk about body malodor two types of acids are at work- Propionic acid and Isovaleric acid.

  • Propionic acid (propanoic acid) is commonly found in sweat when propionic bacteria that live in the ducts of the sebaceous glands of adults and adolescents break amino acids down into propionic acid. The smell of propionic acid is somewhat similar to that of vinegar.
  • Isovaleric acid (3-methyl butanoic acid) is formed due to the action of the bacteria Staphylococcus epidermidis, which are present in several types of cheese.

Since, sweating is believed to be one of the major causes of body odor it is appropriate to discuss the two types of sweat glands present in our body- Eccrine glands and Apocrine glands. Eccrine glands are present in all areas under the skin and are responsible for regulating our body’s temperature. Sweat from these glands reaches the body through coiled ducts. Apocrine glands are found in the armpits, genital areas, breasts, ears, and eyelids. The apocrine glands are mainly responsible for body odor because the sweat they produce is high in protein which bacteria can break down easily.

Note: The average human body has three to four million sweat glands, that are classified into the above mentioned two types.

Understanding the Chemistry of Body Odor

Several compounds are responsible for a variety of body odors, each one being a cocktail of many different chemicals. Metabolic body malodor occurs when one or more of our internal cell enzyme(s), such as the Flavin containing mono-oxygenase3 (FMO3) metabolic enzyme, is deficient. Owing to the deficiency, the enzyme is unable to oxidize odorous substrates to a non-odorous form. As a result, a significant amount of the odorous un-metabolized volatile organic compound (VOC) builds up in the body. Some examples of this condition include Trimethylaminuria (TMAU), Dimethylglycinuria, Isovaleric Acidemia, and others. These conditions are caused mainly due to genetic defects which result in the deficiency of one or more cell enzymes, particularly the group of xenobiotic metabolic enzymes. This condition can also be termed as ‘systemic body odor’ or ‘cell-enzyme saturated body odor’.

Types of Metabolic Body Odors

  1. Trimethylaminuria: This is the only recognized metabolic body odor syndrome to be documented by more than one researcher at present. It is a rare metabolic disorder where Trimethylamine is released in the person’s sweat, urine, and breath, giving off a strong fishy odor or strong body odor.
  2. Osmidrosis or bromhidrosis: This is caused by a water-rich environment that supports bacteria resulting in an abnormal increase in perspiration. This condition is particularly strong in the case of underarms and may be referred to an axillary osmidrosis in such a scenario.
  3. Isovaleric Academia: This is a very serious metabolic disorder caused due to lack of the enzyme Isovaleryl coenzyme A dehydrogenase. One of the tell-tale symptoms is a sweaty feet body odor due to high levels of isovaleric acid.
  4. Hypermethioninemia: This is to do with subnormal function of the enzyme L-methionine S-adenosyltransferase. They will have normal homocysteine levels, but are expected to have relatively raised methionine plasma levels. Some may have raised levels in their urine of dimethylsulfide.

Reasons for Metabolic Body Malodors:

  1. One or more cell enzymes not functioning at normal levels– This could be due to a metabolic disorder inherited in an autosomal recessive manner, such as in Primary Trimethylaminuria, where the person does not have normal capability of oxidizing odorous trimethylamine (TMA) into non-odorous trimethylamine-n-oxide (TMAO) due to genetic causes.
  2. Abnormal amounts of volatile organic compounds (VOCs) absorbed into the bloodstream– When the person is absorbing too many odorous compounds into the main circulation, basically overloading the enzymes that usually oxidizes such compounds, abnormal amounts of volatile organic compounds are absorbed into the bloodstream and transported throughout the body. For instance, those who eat too much garlic or curry may smell of these substances after consuming them. Secondary Trimethylaminuria is another example, involving a gut microbial imbalance, or dysbiosis.

Interesting Fact– It is noticed that metabolic body odors are not obvious to family and doctors. This may be due to the fact that very few sufferers of metabolic body odors seem to smell all the time and might not be giving off body odor at the time of the doctor’s visit. In the case of family members or relatives, they might become ‘desensitized’ to the odor problem (acclimatization), especially with prolonged exposure.

Top 10 Ways to Eliminate Tough Body Odor Problems

There are several ways in which you can fight body odor to eliminate the embarrassing smell. While some of them are related to basic hygiene, others involve the use of special products and formulations to fight off the chemicals that cause body odors.

  1. Keep yourself clean– Taking a regular bath not only washes off the sweat but also reduces the number of bacteria present on the skin. Washing the areas prone to sweating thoroughly can significantly reduce body odor. Using an antibacterial soap rather than a regular one during a bath can also help.
  2. Use ODORBAR® for deodorizing sensitive areas– As we have discussed before, some parts like underarms, feet, and groin tend to smell more than the rest of the body. You can use ODORBAR Everlasting Body Odor Deodorizer Soap to tackle these tough ‘odor hot spots’ very effectively. Simply rinse these areas with ODORBAR® while showering and smell the difference!
  3. Keep your wardrobe clean– Change clothes often when you’re sweating heavily as fresh clothes keep body odor down. Do not neglect to change your socks and wear a fresh pair every day. Hang a SMELLEZE® Reusable Closet Deodorizer Pouch in your closet and insert them in your drawers to keep them fresh and clean.
  4. Use a deodorizing laundry additive– If you have particularly smelly clothing that you are having problems cleaning properly, use ODOREZE® Natural Clothing Smell Eliminator and Laundry Additive to pre-soak your clothes to get all the nasty odors out or simply add to your wash machine.
  5. Deodorize your shoes nightly– Simply insert SMELLEZE® Reusable Foot & Shoe Odor Eliminator Pouches in your shoes overnight to keep them smelling fresh and reducing foot odor.
  6. Control embarrassing flatulence smell– Simply insert SmellRid® Charcoal Flatulence Pads in your underwear to stop those nasty fart smells in their track! You’ll never have to worry about passing gas again.
  7. Use an antiperspirant– It is recommended to use a strong antiperspirant at bedtime so that the product can do its job while you are sleeping and not sweating. If you apply antiperspirants after showering in the morning, the sweat you accumulate will wash away the product and render you defenseless against daytime sweating. Understand that there is a difference between deodorants and antiperspirants, as deodorants only mask the smell caused by sweating while an antiperspirant is a chemical agent that reduces sweating. Some antiperspirants contain a deodorant.
  8. Cut down on ‘offensive’ foods and drinks– The food one eats has an impact on the person’s body odor. Some foods like hot peppers and other spices make you sweat more. The aroma of food items such as onion and garlic can be carried in the sweat, making you smell bad. Drinks with caffeine or alcohol may also cause you to sweat more. So, it is advisable to cut down on the intake of such foods if you wish to prevent bad body odor.
  9. See a doctor– In some cases, like hyperhidrosis (excessive sweating), a visit to a doctor is advisable as this condition might be a result of some serious medical problem. For some body odor conditions, taking proper medications is the best way out.
  10. Try Hydrogen Peroxide– You can use a solution of hydrogen peroxide (1 teaspoon of peroxide-3%) with 1 cup (8 ounces) of water. Wiping smelly areas with a washcloth dipped in this solution will help in removing some of the bacteria.

The above discussion is intended to help you understand the background of body odor, its causes, chemical composition, and how to get rid of the smell. For the best body odor removal products, please visit

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