Urine Smell: What Does It Mean?

Most of the time, you go to the restroom and the pee that comes out is … well, hardly notable. But then there are other days when the urine flows and your nose immediately picks up a certain funkiness.

Consider it a whiff of information, as the smell of your urine can offer important insight into what’s happening inside your body.

Let’s learn how to sniff out the clues with urologist Petar Bajic, MD.

What urine odors might mean

Most urine odor can be explained simply by diet, vitamins, medications and hydration levels. But sometimes, that malodorous stream serves as a warning sign of an underlying health issue that deserves attention, notes Dr. Bajic.

For instance:

Pee that smells like ammonia

If you detect a hint of ammonia in your urine, it could be a sign of a urinary tract infection (UTI). The odor suggests that bacteria may be swimming around in your urinary system, most likely in your urethra, kidneys or bladder.

Urine showing signs of a UTI also may be cloudy or even a bit bloody. Peeing may also become painful — a symptom made even worse by the fact that you may feel the need to urinate more often. A fever and mental confusion are other tell-tale accompanying signs.

If you have multiple symptoms, schedule a visit with a healthcare provider.

UTIs are pretty common, sending approximately 10 million Americans to the doctor every year for antibiotic treatment, says Dr. Bajic. Women and people assigned female at birth and older adults are more prone to getting the infection.

Other potential causes of urine that carry the whiff of ammonia include:

• Kidney stones or kidney disease.
• Liver disease.
• Menopause.
• Prostate infection.
• Sexually transmitted infections such as chlamydia. (The symptoms here are similar to a UTI, with one noticeable difference: The addition of a pus discharge.)

An ammonia-like odor can also be linked to dehydration and certain foods and vitamins, as mentioned previously. So, if the smell pops up and disappears quickly, there’s little reason for concern. But if it lingers, get checked by a medical professional.

Fruity or sweet-smelling pee

Pee with a sugary or fruity fragrance can serve as a warning sign of diabetes or hyperglycemia (high blood sugar), says Dr. Bajic. The sweet smell comes from your body unloading excess glucose, or sugars.

In children, particularly newborns, sweet-smelling tinkle might indicate maple syrup urine disease. This rare, life-threatening metabolic disorder prevents the body from breaking down specific amino acids found in food.

The underlying message here? Urine that smells sweet shouldn’t be ignored. Check in with a healthcare provider.

Foul-smelling pee

There are plenty of innocuous reasons for pee to have notes of sulfur, like asparagus, garlic or onions. But if you haven’t recently taken a trip to Flavortown, foul-smelling urine could indicate one of two rare metabolic disorders.

Trimethylaminuria, also known as TAMU or fish odor syndrome, is a rare condition in which your body is unable to process trimethylamine — which, as it happens, is a particularly stinky chemical. The unfortunate result: Pee, breath and sweat that smells like, you guessed it: rotting fish. This condition can be inherited or acquired. While it’s an unpleasant condition, it isn’t especially dangerous.

The opposite is true of tyrosinemia, which has three distinct types (type I, II, and III). Infants with this (extremely rare) genetic disorder can’t break down an amino acid called tyrosine, which is foundational to most proteins. The resulting tyrosine buildup can cause a wide range of severe complications. Tyrosinemia is exceedingly rare, but if your infant’s urine is foul-smelling, you should talk to your pediatrician anyway, just to be safe.

Why else does urine smell?

For the most part, urine carries very little odor. The reason why is simple: It’s about 95% water. The remaining amount is mostly waste products — calcium, nitrogen, potassium and more — which get filtered by your kidneys. That said, there are several harmless reasons your pee may smell:

• You’re dehydrated. If you’re dehydrated, the percentage of water in your pee drops and the filtered waste takes a more prominent role. That creates a stronger smell, explains Dr. Bajic. (Dehydration also turns your urine a darker color, but that’s a different discussion.)
• What you’re eating. Asparagus is infamous for giving urine a pretty strong sulfur smell, for instance. Fast fact: Your body converts an acid in asparagus into sulfur-containing compounds, which creates that pungent result. Brussels sprouts, fish, cumin, onions and garlic also can add a certain zest to urine.
• What you’re drinking. Coffee drinkers also may recognize a certain brewed aroma during a bathroom break. Speaking of brews, alcohol can also make your pee smell.
• What you’re taking. Various medications and supplements can contribute a specific scent to pee.

“This is all completely normal,” Dr. Bajic reiterates. “It reflects the life you’re living.”

Bottom line

There’s usually a pretty basic explanation for urine that smells a bit different. It’s just the way your body functions, notes Dr. Bajic. In most cases, that funk should disappear within a day or so.

But if the smell stays and is accompanied by other symptoms, it’s something that deserves further investigation. Don’t ignore it.