Have you ever noticed that sometimes you don’t smell anything when you sweat, but other times your sweat smells like onions, spices, or even sweetness? The scent can reveal a lot about your health.
Sweat Glands
Let’s get straight to the point: sweat itself is odorless. The reason sweat begins to smell is due to bacteria that live on your skin or in your clothes.
There are two types of sweat glands: eccrine and apocrine glands. Eccrine glands are found all over your body and produce clear, odorless sweat, which helps regulate your body temperature. Apocrine glands, on the other hand, are located in your armpits, genital area, and around your nipples. The sweat produced by these glands is thicker and contains more proteins, which bacteria love to break down. This process results in the well-known body odor.
Sweat is made up of water, salt, fats, and proteins. When sweat reaches your skin, bacteria naturally present on your skin break down these substances. This often leads to the unpleasant smell we associate with sweat.
Sweat Odor
The odor of sweat is primarily caused by bacteria, but factors such as stress, diet, clothing, and medication can also affect it. The scent can range from sour or sulfurous to even sweet, depending on the circumstances.
Sour Smell
Sweat from the apocrine glands, such as in your armpits, is usually thicker and contains more proteins. When this sweat is broken down by bacteria on your skin, it can develop a sour smell. This is because certain bacteria break down substances like fatty acids, which causes a sour odor typical of body odor.
Hormonal fluctuations can also alter the scent of sweat. Increased production of hormones like estrogen and testosterone affects the function of the apocrine glands and can lead to a stronger, sour smell.
Sulfur-like Smell
Some bacteria, like Corynebacterium, produce sulfur compounds that create a strong smell. This scent can resemble rotten eggs and is often present after stress or intense physical exertion.
Stress increases the activity of the apocrine sweat glands, which can lead to sweat with a stronger odor. It can also disturb the balance of bacteria on your skin, intensifying the sulfur-like smell.
Additionally, poor hygiene can worsen the odor. If sweat isn’t washed off quickly, it can stay in contact with bacteria on the skin, making the smell stronger, especially in warm, humid areas like the armpits.
Medications can also affect the scent of your sweat by altering its composition or the bacteria on your skin. Certain foods like garlic, onions, and spicy dishes can contribute to a sulfur-like smell as they contain sulfurous compounds that are excreted through sweat.
Ammonia-like Smell
After intense physical exercise or with a high-protein diet, your sweat may have an ammonia-like smell. This happens because the body breaks down proteins into amino acids, some of which are converted into ammonia. If you don’t drink enough water, it becomes harder to properly eliminate these substances, which can intensify the smell.
People who eat a lot of protein, such as bodybuilders or meat-eaters, break down excess protein in their bodies. This produces ammonia, which is then released through sweat.
An ammonia-like smell can also indicate health problems, such as metabolic disorders, like the rare condition phenylketonuria.
Sweet Smell
In some cases, like with certain medical conditions such as diabetes, sweat can have a sweet smell. This may indicate poor blood sugar regulation, where the body burns fatty acids instead of glucose, resulting in a sweet odor in the sweat.
Hormonal changes, such as during pregnancy or with the use of certain medications (e.g., corticosteroids), can also influence the scent of sweat. In some cases, this can make the odor sweeter due to changes in the body’s chemistry.
In rarer instances, a diet rich in sugar or artificial sweeteners can affect the smell of sweat. However, this is usually a temporary change that stops once the diet is adjusted.