Does Your Sweat Smell Like Ammonia? Causes and Solutions

Ammonia is a colorless gas consisting of nitrogen and hydrogen. It is present in small quantities in air, water, and soil. Ammonia has a sharp, pungent odor that some people describe as smelling like urine, fish, or chemicals. If you develop body odor resembling the smell of ammonia, your sweat may be the source of the problem.

Why does my sweat smell like ammonia?

Sweating is the body’s natural way to release heat. When you feel hot due to exercise, weather, illness, or stress, sweating allows your body to regulate its internal temperature to keep it functioning properly.

While it is common to think that sweat smells, it is actually odorless. Odor only develops when sweat interacts with bacteria on the skin. These bacteria digest the proteins and fats found in sweat, releasing often unpleasant smells.

The human body produces ammonia as a byproduct of protein digestion. The liver converts ammonia into a substance called urea, which exits the body in the urine. Sweat contains small amounts of ammonia since not all of it is eliminated by the kidneys. Normal amounts of ammonia present in sweat do not lead to any noticeable odors.

However, if your sweat begins to smell particularly foul, this could be a sign that too much ammonia has accumulated in your blood. A number of reasons explain why this can happen:

Diet

Consuming a diet rich in proteins and low in carbohydrates is one potential explanation for why your sweat smells like ammonia.

Ammonia is produced when the amino acids found in proteins are broken down by bacteria in your intestines. Therefore, eating excessive quantities of proteins found in meats and dairy can potentially increase ammonia levels in the body. The ketogenic diet and carnivore diet are examples of high-protein, low-carb diets. Not consuming enough carbohydrates also means that your body depends more heavily on using protein for energy.

Two small studies showed that blood ammonia levels rose in healthy women and men in the hours following a high-protein meal. Although not confirmed in humans, a computer simulation of protein metabolism also demonstrated that increasing dietary protein intake can increase blood ammonia levels.

Exercise

Exercising in the absence of a sufficient supply of carbohydrates ramps up your body’s dependence on proteins as a source of energy. The more proteins your body breaks down — either from diet or your muscle — the more ammonia it creates. This ammonia makes its way into the sweat during and after exercise.

A small study showed that the concentration of ammonia found in the sweat and blood of rugby players increased during competition. Another small study found that compared to a normal diet, exercising on a low-carbohydrate diet led to increased blood and sweat ammonia levels.

Additionally, make sure you drink enough fluids when exercising. Dehydration can potentially worsen your sweat’s odor because not having enough fluid further concentrates any existing ammonia.

Health conditions

Even healthy people can experience odorous sweat under the right circumstances (for example, exercising too much while on a high-protein, low-carbohydrate diet). However, certain medical conditions can further contribute to your sweat smelling like ammonia.

Hyperhidrosis

Hyperhidrosis is a condition characterized by excessive sweating. People with hyperhidrosis can sweat profusely even when they are sitting still in a cool room.

In primary focal hyperhidrosis, abnormal nerve signals cause sweat glands to become overactive, especially in the armpits, hands, and feet. As a result, they can produce sweat even when there is no apparent trigger.

In secondary hyperhidrosis, excessive sweating is due to another medical condition. There are many potential causes of secondary hyperhidrosis, including hyperthyroidism, obesity, diabetes, neurological disorders (e.g., Parkinson's disease), or side effects of medications (e.g., antidepressants, antipsychotics, antibiotics).

Liver disease

The liver converts ammonia into a less toxic compound called urea, which is then eliminated by the kidneys. When liver function is impaired (such as in cirrhosis), it cannot perform its normal detoxifying functions, leading to a buildup of ammonia in the blood.

Liver disease does not typically cause sweat to smell like ammonia, but if it does, other symptoms are typically also present. This may include a yellowing of the skin and eyes, abdominal pain, and confusion.

Kidney disease

People who have kidney problems, especially late-stage renal failure, have difficulty excreting ammonia from the body in the form of urea. Too much urea can accumulate in the blood, leading to a buildup of ammonia as well.

A person with kidney disease who notices that their sweat smells like ammonia may also experience other symptoms due to the buildup of urea in the blood. These can include nausea, vomiting, weight loss, drowsiness, and fatigue.

Diabetes

Diabetes increases the risk of both kidney and liver disease. In this way, a patient with diabetes may have odorous sweat not because of the diabetes itself but because of its complications.

Another way in which diabetes can change the smell of sweat is by the buildup of a molecule in the blood called acetone. This can occur in people typically with type 1 diabetes when the body runs low on insulin.

When this happens, the body undergoes a process called ketosis whereby it burns fat for energy, giving off byproducts called ketone bodies (including acetone). Acetone has a fruity odor, however, distinguishing it from the foul smell of ammonia.

Trichomycosis

Trichomycosis is a bacterial infection of the hair under the armpits and rarely the pubic area. While many people do not have symptoms, others can develop a foul odor in infected areas. They can also experience excessive sweating, which may be discolored, leading to stained clothing. Sometimes, small red, yellow, or black masses can be found around the infected hair shafts.

Trimethylaminuria

Trimethylaminuria is also called ‘fish odor syndrome’ because of the distinct body odor experienced by people with the condition. It is a rare inherited disorder in which the body is unable to break down a molecule called trimethylamine produced by bacteria in the gut. Trimethylamine accumulates in body fluids such as sweat and causes them to smell like rotten fish.

Stress

Sweating can occur when your body is under stress, sometimes called ‘stress sweat.’ This is produced by the apocrine sweat glands, which are concentrated in specific areas of the body, such as the armpits, groin, and breasts.

Unlike the eccrine sweat glands, which produce watery sweat mostly consisting of electrolytes such as sodium, the apocrine sweat glands make thicker sweat that contains proteins and fats — a perfect meal for the bacteria on your skin. This is why body odor can arise when you sweat under pressure, stress, or anxiety.

Hormones

In women, estrogen and progesterone have important roles in regulating body temperature. Therefore, fluctuations in hormone levels that occur prior to menstruation, during pregnancy, or around menopause (‘hot flushes’) can cause excessive sweating.

It is unclear how testosterone levels affect sweat odor, although high levels of an enzyme responsible for processing testosterone to dihydrotestosterone exist in apocrine sweat glands, suggesting that high dihydrotestosterone levels may play a role in odor formation.

How do I get rid of the ammonia smell in my sweat?

Getting to the root cause of the ammonia smell in your sweat is the only way to permanently resolve the problem. However, anyone can practice the following strategies at home to reduce sweat odors.

Stay hydrated

Not drinking enough fluids causes organic substances in your sweat to become more concentrated, leading to worsening odors. Increasing your fluid intake, on the other hand, makes your sweat more dilute.

Adjust your diet

Maintaining a balanced diet consisting of carbohydrates, fats, and proteins can prevent your body from relying too much on proteins for energy. Over-reliance on protein sources such as meats can lead to increased production of ammonia, as previously discussed.

Bathe regularly

Bathing regularly is the best way to temporarily eliminate residual sweat on your skin, as well as the bacteria that can produce foul odors from your sweat.

Wear breathable fabrics

Breathable fabrics help decrease the amount of sweat that stays on your skin. In particular, moisture-wicking clothing pulls moisture away from the skin to the exterior of the fabric, allowing it to evaporate more quickly. Look for polyester, polypropylene, or nylon materials for your exercise apparel, and avoid cotton, which retains moisture.

Change clothes after exercising

Clothing, especially cotton-based apparel, tends to absorb moisture from the skin. This is why it can take a long time for you to get dry after a workout. Wearing sweat-soaked clothing can keep you smelling poorly, and a simple workaround is to put on a new set of clothes after you sweat.

Maintain clean footwear

Bacteria thrive in damp environments, such as inside shoes and socks, particularly since the feet produce a lot of sweat. Footwear made of non-breathable materials can also trap moisture, further feeding the bacteria on your feet. Washing your footwear regularly can eliminate this trapped moisture and keep you from developing foot odors.

Lemon juice and apple cider vinegar

A 2023 TikTok trend found people applying lemon juice to their armpits to eliminate odor. The reason this works is that lemon juice contains citric acid, which possesses antibacterial properties.

Like lemon juice, apple cider vinegar also possesses antibacterial activity. Because apple cider vinegar is strong, it must first be diluted with water (1 tsp for every cup of water) before applying it to the armpit or other odorous areas.

Lemon juice and apple cider vinegar may be reasonable home-based alternatives to deodorants, although neither are permanent solutions to eliminating sweat odors.

Medical treatments

If the above strategies do not eliminate the ammonia smell in your sweat, you may need to consider medical options. Ultimately, a doctor should evaluate you to determine the underlying cause of your sweat odor. For example, the root cause may be liver disease, kidney disease, menopause, hypothyroidism, or trichomycosis. In such cases, the condition will need to be treated or prevented from worsening.

Besides treating the underlying cause, some specific medical therapies exist for primary focal hyperhidrosis. These include:

• Prescription antiperspirants. This is the first-line therapy and typically contains an aluminum-based compound stronger than what is found in nonprescription antiperspirants.
• Topical glycopyrronium. An alternative first-line therapy, glycopyrronium belongs to a drug class called anticholinergics that blocks the action in sweat glands.
• Botulinum toxin (Botox). Botox can be injected into the armpit to decrease sweat production.
• Microwave thermolysis. Microwave energy is used to disable sweat glands, but this treatment is expensive and often unavailable.
• Iontophoresis. An electric current is administered through water to block sweat glands in the hands or feet.

Ways to prevent ammonia sweat smell

While the ammonia sweat smell is not always preventable, here are some strategies you may want to consider:

• Moderate-intensity exercise. If you are exercising too much or too intensely, especially without consuming enough carbohydrates, your body relies more on protein for energy. Higher protein metabolism leads to more ammonia production.
• Reduce stress. By reducing stress and other emotional triggers, you may be able to reduce the amount of ‘stress sweat’ your body produces.
• Limit alcohol. Excessive alcohol consumption may cause dehydration if you don’t also drink enough water. Alcohol reduces the levels of a hormone called vasopressin, which normally causes your body to hold onto water.
• Use deodorants and antiperspirants. Deodorants can effectively mask the smell of sweat but do not treat its cause. Antiperspirants, on the other hand, contain aluminum-based salts that temporarily block sweat pores, reducing how much sweat reaches the surface of the skin. Commercial products often contain a combination of deodorant and antiperspirant.

You should speak with your doctor if your ammonia-smelling sweat does not improve with changes to diet, exercise, and stress, which are the most likely causes of sweat odor in healthy people. Persistent ammonia-smelling sweat may signify an underlying health condition, especially if you have other symptoms, such as muscle weakness, changes in urination, or unexplained neurological symptoms.