Not all types of sweat have an odor. However, sometimes sweat can smell like ammonia. This can be due to a high protein diet, exercise, or health conditions such as kidney disease.

The purpose of sweat is to help the body cool down. Sweat droplets transfer body heat onto the surface of the skin, where they evaporate. This can make the skin feel cool and reduce a person’s body temperature.

This article explains why a person’s sweat may smell like ammonia and what treatment options are available.

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Sweat can act as a barrier against bacteria on the skin, and it can also moisturize the skin.

Sweat contains water and sodium chloride, as well as small amounts of:

  • potassium
  • calcium
  • ammonia
  • urea
  • lactate
  • ethanol

A person may sometimes be able to smell the ammonia content in their sweat.

Sweat glands all over the body release sweat. There are three types of sweat glands, which are called the eccrine, apocrine, and apoeccrine glands.

Eccrine glands are the most abundant across the body. This type of sweat gland produces the most sweat, but it does not have a smell.

Apocrine glands are found in specific areas of the body, such as the breasts, face, scalp, perineum, and the underarms.

The apocrine glands produce sweat that comes through hair follicles rather than through the pores on the skin. Sweat from apocrine glands can have an odor. It contains high levels of lipids, as well as sugars and ammonia.

Apoeccrine glands are only located in the underarms. Apoeccrine glands release sweat onto the skin’s surface in the form of salt water.

Sweat from apoeccrine glands is not thought to help regulate a person’s temperature as it cannot evaporate easily from the underarms.

Ammonia (NH3) is a colorless gas that is a compound of nitrogen and hydrogen. It has a strong odor that smells like urine or sweat.

Ammonia occurs naturally in water, soil, and the air, and is also found naturally in plants, animals, and the human body.

The human body makes ammonia when it breaks down protein into amino acids. The liver then converts ammonia into urea before it leaves the body through urine or sweat.

There are many possible causes of sweat smelling like ammonia. These include:

Diet

A person’s diet can make their sweat smell like ammonia.

A person who eats a diet high in protein but low in carbohydrates may produce ammonia that the body then releases in sweat.

The body usually uses carbohydrates for energy by converting them into glucose because carbohydrates are the fastest energy supply. However, if there aren’t enough carbohydrates, the body will use protein for energy.

Protein breaks down into amino acids, which the body converts into ammonia. The body then releases this ammonia through urine and sweat, which may produce an odor.

Dehydration can also make the sweat smell like ammonia. This is because the body needs water to get rid of ammonia through sweat.

If there is not enough water to dilute the ammonia as it is released by the body, the smell of ammonia may be stronger.

Exercise

Some research suggests exercise affects ammonia levels in sweat. A 2007 study found that ammonia levels in sweat increased as a person exercised more intensely.

A 2005 study found that while ammonia levels in sweat increased significantly during exercise, ammonia levels in sweat reduced over the 24 hour period after exercise and remained low after 72 hours.

This suggests a person may find their sweat smells most strongly of ammonia during or just after exercise.

Health conditions

Certain health conditions can cause a person’s body odor to change. They include:

Hyperhidrosis

Hyperhidrosis causes excessive sweating from the eccrine glands. A 2016 study estimated 15.3 million people in the United States live with hyperhidrosis.

There are two types of hyperhidrosis:

  • Primary focal hyperhidrosis: This type of hyperhidrosis can affect the underarms, hands, feet, and forehead. Primary focal hyperhidrosis is not due to an underlying health condition or a side effect from medication.
  • Secondary hyperhidrosis: This type of hyperhidrosis is due to an underlying health condition or a side effect of medication.

If a person sweats a lot, sweat may build up on their skin and interact with bacteria. This can cause an odor to develop, which may smell like ammonia.

Kidney disease

Kidney disease can cause a person’s body odor to change.

The kidneys are responsible for removing urea from the body. However, if the kidneys are not working properly, urea may enter into the bloodstream instead. This is called uremia, and is a serious symptom of kidney failure.

If a person has high levels of urea in their body, the body may release urea through sweat and cause an odor.

According to the National Kidney Foundation, the main causes of kidney disease are diabetes and high blood pressure, which accounts for up to 66% of cases.

Diabetes

A complication of diabetes is a condition called diabetic ketoacidosis (DKA).

DKA develops when the body burns fat for energy if there is not enough insulin to use glucose in the cells.

When the body burns fat for energy, it produces ketones. A type of ketone called acetone can make the breath smell fruity or change a person’s body odor.

If the level of ketones becomes too high, the blood can become too acidic, which can be life-threatening.

According to the American Diabetes Association, DKA is rare in people with type 2 diabetes, but it can still develop in anyone.

DKA produces symptoms including:

  • frequent urination
  • thirst
  • very dry mouth
  • high blood sugar levels
  • high ketone levels in urine
  • vomiting

Trichomycosis

Trichomycosis is a bacterial infection that affects the hair in the underarms. According to a 2013 study, it can affect pubic hair in rare cases.

The bacteria Corynebacterium causes trichomycosis and produces yellow, black, or red nodules that stick to the hairs.

Odor was a symptom of trichomycosis in 35.7% of cases, according to the 2013 study.

Trimethylaminuria

Trimethylaminuria is a rare condition. Increased levels of the compound trimethylamine (TMA) in the body cause trimethylaminuria. TMA has a fish-like smell. The body releases TMA through the urine, sweat, or breath.

Bacteria in the gut produces TMA. According to the National Institutes of Health, a person with trimethylaminuria may have inherited a faulty gene that means the body cannot break down TMA properly.

Treatment can include taking activated charcoal supplements to help remove excess TMA from the body. B12 supplements, antibiotics, and probiotics may also help.

Meat consumption

Dietary choices may affect body odor, including whether people eat meat or not.

An older study from 2006 found that participants on a meat diet had body odor which others perceived as less attractive than the body odor of participants on a non-meat diet.

Dairy consumption

In rare cases, eating eggs and milk can cause a person’s sweat to smell different. This is because dairy products produce trimethylamine when the body digests them, which has a strong, fishy smell.

A 2015 study found that trimethylamine-N-oxide (TMAO) levels increased after the participants ate dairy products. Trimethylamine produces TMAO.

Although trimethylamine-N-oxide is odorless, if a person cannot digest trimethylamine properly, the body may release it through sweat and cause body odor.

Spices and seasonings

Spices such as cumin or curry can change a person’s sweat odor. This is because they can create sulfur-like compounds when digested, which can react with sweat and cause odor.

Onions, herbs, and garlic can also have the same effect.

Stress

A person may sweat due to stress. The International Hyperhidrosis Society states that the apocrine glands are responsible for producing stress-related sweat.

Sweat from the apocrine glands is thicker and contains more proteins and lipids. When this type of sweat sits on the skin and mixes with bacteria, it can create a smell.

Hormones

A person’s hormones may change during puberty, menstruation, pregnancy, and menopause.

Decreasing estrogen levels during menopause may cause sweating, which can increase odor if it mixes with bacteria on the skin.

People can take several steps to prevent sweat smelling like ammonia. These include:

Changing the diet

To prevent the body from using protein as energy after exercise, which may cause their sweat to smell like ammonia, a person can increase the amount of carbohydrates in their diet.

Whole grains, vegetables, fruits, and beans are healthy sources of carbohydrates.

Additionally, if a person notices that certain foods, such as fish or dairy, make their sweat smell like ammonia, they can reduce their intake of those foods or remove them from their diet.

Drinking more water

Increased water intake can dilute sweat and make its odor less noticeable.

Deodorants and anti-perspirants

A person can use deodorants to cover up the ammonia smell from sweat.

They can also try antiperspirants, which block the sweat glands and stop sweating from happening. This can reduce the amount of sweat on the skin that mixes with bacteria and produces odor.

Changing clothes

A person can try changing their clothes more frequently to keep their skin dry and free of bacteria that can react with sweat and cause odor.

Washing

Antibacterial soap can fight bacteria on the skin. This will keep the skin clean and fight any odor from bacteria mixing with sweat.

Antifungal creams or powders can also help a person reduce their risk of fungal infections.

Reducing stress

If a person notices they sweat more with stress, they can try evaluating the sources of stress in their life.

If they are able to reduce their stress levels, they may sweat less and reduce any odors that were occurring because of their stress.

A person whose sweat smells like ammonia should look out for symptoms of an underlying condition.

If their urine has a strong ammonia smell, this may be a sign of diabetes. If a person notices blood in their urine, or that their urine is foamy, this may be a sign of kidney disease.

Fungal infections may cause rashes, sores, or blisters. A person should contact a doctor if they think they may have a fungal skin infection.

To help control body odor, the International Hyperhidrosis Society recommends:

  • keeping the skin dry
  • washing with antibacterial soap
  • reducing sweating by using antiperspirants
  • masking odors with deodorants

A person can also contact a doctor to discuss the following medical treatments:

Microwave thermolysis

Microwave thermolysis is a treatment that uses microwave energy to stop the sweat glands from working properly.

A 2013 study found that microwave thermolysis was an effective treatment for sweat that produced odors.

Botox

The U.S. Food and Drug Administration (FDA) has approved the use of onabotulinumtoxinA, or Botox, to treat excessive sweating.

Botox can be an effective treatment for hyperhidrosis as it blocks the chemical that signals for the sweat glands to produce sweat.

According to the International Hyperhidrosis Society, Botox can cause an 82-87% reduction in underarm sweating.

Botox injections can be effective in stopping underarm sweating for 4-12 months, and possibly up to 14 months.

Prescription antiperspirants

The International Hyperhidrosis Society recommends antiperspirants to help control excessive sweating and body odor.

Prescription antiperspirants may contain higher amounts of active ingredients than over-the-counter antiperspirants.

These active ingredients can include metallic salts such as aluminum chloride hexahydrate.

Prescription antiperspirants are most effective when people apply them both at night and in the morning.

Antibiotics

A person can use antibiotics to treat underlying conditions that cause sweat to smell like ammonia, such as trichomycosis.

Many things can influence the smell of a person’s sweat. Diet, exercise, and bacterial infections may all alter body odor.

A person living with a health condition such as diabetes or kidney disease may also have sweat that smells like ammonia.

A person can try antiperspirants to reduce the amount they sweat, and deodorants to cover up any odors. A doctor can treat any underlying health conditions to help reduce the ammonia smell in sweat.