Does Sweat Smell?2

Does Sweat Smell?2

Sweat and body odor generally go hand in hand, but their relationship is a little more complicated than it seems on the surface. We’ve broken down the role sweat plays in the development of body odor and the causes of extreme body odor, also known as bromhidrosis.

Types of Sweat

Contrary to popular belief, sweat itself is an odorless liquid. That post-workout smell only occurs once the sweat gets broken down by the bacteria that live on our skin. When the bacteria break down the sweat, they release a sulfurous odor that is generally described as “oniony” or “meaty”.

The smell associated with sweat depends on the type of sweat (eccrine or apocrine) that is produced and its subsequent reaction once it encounters bacteria on the surface of the skin. The two types of sweat play a different role in the human body and have equally different compositions and reactions on the skin.   

Eccrine Sweat Glands

  • Eccrine glands are found all over the human body and produce a clear odorless sweat (diluted saltwater) in response to an increase in body temperature. This is the sweat we produce following a gym workout, a run, or after being exposed to hot temperatures. It’s our body’s way to cool down and prevent overheating.

Apocrine Sweat Glands

  • Apocrine glands are found in limited regions on the body, most densely in the underarms. These glands grow in relation to hair follicles and produce a thick, initially odorless liquid that contains proteins, sugars, ammonia, and fatty acids.


Why does sweat smell?

As is the case with many things in the human body, it all comes down to bacteria. Neither eccrine nor apocrine sweat have an initial smell, but both are responsible for body odor when broken down.

Eccrine sweat is generally odorless, but it can start to smell if left on the skin long enough for bacteria get a chance to break down the stale sweat. Therefore, it is important to practice proper hygiene, and shower and wash your clothes after a particularly sweaty day. Eccrine sweat can also be malodorous if you have ingested certain substances such as foods containing sulfur (eggs, onions, garlic, etc.) or alcohol. Some medications are also known to cause foul-smelling sweat.

Apocrine sweat secretions are responsible for what we associate with typical body odor. This type of sweat is initially odorless, but when it reaches the surface of the skin, the bacteria that live on the skin quickly break it down, which produces an offensive body odor.


Body odor is aggravated if there are more bacteria present on the skin or if the level of apocrine sweat production is high. Therefore, those who suffer from excessive sweating of the underarms, also known as axillary hyperhidrosis, are more likely to also suffer from excessive body odor.

What bacteria cause body odor?

Human body odor is most closely linked with the underarms, as it’s generally a moist, warm, and dark area which is the perfect environment for bacteria to grow and multiply. The scent is released once bacteria break down the sweat and form something called thioalcohols, which have scents comparable to sulfur, onions, or meat. These molecules evaporate from the underarm, which is what leads to the smell associated with body odor. Researchers recently concluded that the bacteria responsible for body odor are staphylococcus hominis, which are considered the worst offenders.

When is body odor considered a medical condition?

Extremely foul body odor is a medical condition called bromhidrosis. It is generally associated with another medical condition called hyperhidrosis, which is characterized by excessive sweating. An excess in sweat production (especially in the case of underarm hyperhidrosis) means that there is more sweat for the bacteria to break down, which releases even more odor. The two are closely linked, but not everyone who suffers from hyperhidrosis also suffers from bromhidrosis, and vice versa.

Apocrine bromhidrosis

  • Apocrine bromhidrosis is the most common type of the condition, which almost exclusively affects the underarm area. The ammonia and fatty acids present in apocrine sweat release a musty, pungent odor when broken down by bacteria.

Eccrine bromhidrosis

  • Eccrine bromhidrosis is mostly linked to the ingestion of certain types of strong-smelling foods such as garlic and onions. It can also be the result of taking certain medications or various metabolic conditions.  


How can I get rid of body odor?

If your body odor is linked to excessive sweating, then the best way to treat it is by treating the excessive sweating first (the root of the problem). An effective way to treat hyperhidrosis is with tap water iontophoresis, which is a natural, non-invasive, and drug-free treatment option. Dermadry’s home-use iontophoresis machine can provide up to 6 weeks of dryness at a time. Learn more by browsing our product range below!

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