Urine does not usually have a strong odor to it, but a person may notice an ammonia odor at times. Possible causes include certain foods, supplement use, a urinary tract infection, a liver or kidney problem, or dehydration.

Urine is the body’s liquid waste. It is made by the kidneys, which filter toxins out of the blood.

Urine contains water, salt, urea, and uric acid primarily. Urea is expelled in the form of sweat through the body, while uric acid is the result of urine metabolism.

Changes in urine smell and color offer insight into a person’s health, diet, and lifestyle choices. These choices may contribute to an ammonia smell but are not the only causes.

Fast facts on urine smelling like ammonia

  • Urine is mostly water and usually has only a weak odor.
  • There are several causes of an ammonia odor from urine.
  • Ammonia-smelling urine is common and mostly harmless.
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Most of the time, this occurrence is nothing to cause alarm. There are times, however, when ammonia-smelling urine indicates a health problem.

Dehydration

Dehydration can cause an ammonia smell. Dehydration occurs when someone doesn’t drink enough fluids or has a significant fluid loss due to vomiting or diarrhea.

Ammonia odor happens when chemicals in urine are concentrated due to a lack of water.

In addition to an ammonia-like odor, another telltale sign of dehydration is bubbles in a person’s urine. And if someone is dehydrated, their urine is dark honey or brown color, rather than a pale yellow or gold.

Urinary tract infections

According to research from the Washington University School of Medicine in St. Louis, Missouri, urinary tract infections (UTIs) are the most common bacterial infections worldwide, affecting up to 150 million people each year.

Additional figures for the United States include 10.5 million doctor visits and up to 3 million emergency room visits for UTI symptoms.

UTIs tend to affect people born female more, but people born male can also develop UTIs. These infections are the result of bacteria entering the urinary tract. The bacteria make urine smell unpleasant and cause it to be cloudy or bloody.

Pregnancy

Pregnant people have a higher risk for UTIs, increasing their chances of having ammonia-smelling urine. One report from the U.S. Centers for Disease Control and Prevention (CDC) finds up to 8% of pregnant women experience UTIs.

UTIs can cause serious pregnancy complications, including premature labor, low birth weight, and sepsis. Hence, pregnant people should let their doctors know if they experience unpleasant-smelling urine, especially if the smell resembles ammonia.

Pregnancy vitamins can also create a smell of ammonia in the urine. Smelly urine from taking vitamins usually goes away after a short time.

In the absence of other symptoms, such as pain with urination, cloudy or dark urine color, or unusual frequency of urination, there is usually little reason for concern. But recurring ammonia odor in pregnancy should still be brought to a doctor’s attention.

Menopause

Menopause can also increase a person’s risk for UTIs and ammonia-smelling odor, resulting from drops in the female hormone estrogen and loss of vaginal flora, which are the natural and healthy bacteria living in the vagina. Both these changes may cause ammonia-smelling urine.

A further possibility is diet changes during menopause, which can cause an ammonia odor.

Diet

Diet is the most common cause of ammonia-smelling urine in all people. Certain foods, medications, and vitamins can cause changes in urine smell and color.

Asparagus is commonly linked with an ammonia smell, as are large amounts of vitamin B6. Similarly, foods high in protein can increase urine’s acidic properties and cause it to have an ammonia smell.

When diet is the cause of ammonia-smelling urine, the odor disappears once a person eliminates food triggers from their diet. Odor caused by something a person has eaten is usually nothing to worry about.

Kidney or bladder stones

Anyone who develops kidney or bladder stones may experience ammonia-smelling urine.

When stones pass through the urinary tract, the risk for UTIs increases, and they can cause urine to have an ammonia smell.

Kidney disease

Kidney disease causes chemicals in urine to become concentrated and to cause a smell resembling ammonia. Kidney dysfunction can also cause high bacteria and protein levels in the urine, which will contribute to a foul ammonia smell.

Liver disease

Like the kidneys, the liver is responsible for removing toxins from the body and helping it digest food. Infections and diseases of the liver can produce high ammonia levels in the urine and the accompanying pungent odor.

Ammonia levels in blood and urine will increase when the liver is not working as it should. Any continued ammonia odor in urine should be checked by a doctor.

If ammonia-smelling urine occurs every once in a while, it is rarely a reason for concern. However, if the ammonia odor is accompanied by pain or symptoms of infection, including fever, it is time to see a doctor.

A doctor will want to know:

  • how long urine has had an odor
  • how often ammonia odor occurs
  • other symptoms, including blood in urine, back pain, fever, pain with urination, and urgency

A doctor will likely do a physical exam and request urine samples and blood work.

Urine is examined for blood, bacteria, and kidney or bladder stone pieces. Usually, urine testing and blood work can help a doctor make a diagnosis.

A doctor may also request imaging studies to test for kidney, bladder, or liver abnormalities.

Treatments depend on the contributing cause. When diet is causing the odor, lifestyle changes can keep urine smelling and looking healthy.

Stay hydrated

Drinking between 9–13 cups of water daily can reduce the chances of dehydration.

People who notice their urine is dark in color and has an ammonia smell should start drinking water to ensure they are not dehydrated.

Making sure to avoid the common causes of dehydration, such as heat and sweating, can also help people stay hydrated.

Cut down on diet triggers

Anyone who consumes a lot of triggering foods can stop ammonia-smelling urine by cutting those foods out of their diet.

Reducing the intake of offending vitamins and medications can also reduce urine odor.

Pass urine often

Most people urinate when their bladders are full. But urine that is held in can become more concentrated and have a foul odor. Not holding in urine will minimize ammonia odor and infections.

Stay clean

Personal hygiene of the genital area is vital when experiencing a strong ammonia-smelling odor. Ensuring genitals are cleaned well during bathing and completely dried afterward is essential.

It is also a good idea to empty the bladder completely when urinating to avoid remnants of urine dripping onto clothing. Wiping well and rinsing with water, if needed, after urinating can also minimize the bacteria that cause infections and ammonia-smelling urine.

The most common causes of an ammonia smell in a person’s urine are diet, UTIs, dehydration, and hormones. It is important to find out the main cause, especially if it is medical.

Most of the time, staying hydrated, decreasing intakes of trigger foods, vitamins, and medications, passing urine often, and practicing good hygiene can manage ammonia odor in urine.

It is important that ammonia-smelling urine is not ignored, especially if it continues after attempting to resolve it. Ammonia smell may indicate a health problem and should not be ignored.