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Fishy-smelling urine: causes and treatment

by Alivia Nyhan
Published: Last Updated on

The appearance and smell of urine can indicate that something is not right in our bodies. Therefore, it is essential to observe it after each urination as much as possible.

Fishy smelling urine tends to be related to two main situations, the first of which is inherent in urine, which is called trimethylaminuria, and the other is related to a vaginal infection, known as bacterial vaginosis, and other causes such as pregnancy, the consumption of some vitamins and food.

If you want to know more about fishy-smelling urine: causes and treatment, we invite you to continue reading this FastlyHealarticle.

Fish smell syndrome: trimethylaminuria

One of the reasons fishy urine may appear is known as trimethylaminuria (TMAU) or fish smell syndrome. It is an infrequent disease product of a metabolic disorder, generally of a genetic cause, produced by a defect in a liver enzyme responsible for metabolizing and eliminating trimethylamine.

Trimethylamine is a derivative of the intestinal bacterial breakdown of amino acids, such as choline and trimethylamine oxide. The disease occurs when trimethylamine is not eliminated and accumulates in the body. This disease has two types:

  1. The primary is inherited in a recessive autonomic manner.
  2. The secondary product of damage to kidney and liver function.

The Spanish Journal of Human Nutrition and Diet indicates that the incidence of heterozygous carriers varies between 0.5% and 11% of the primary form of trimethylaminuria [1].

The fishy smell usually begins to be released in different ways after its accumulation in the body:

  • By urine.
  • By breath.
  • Because of the sweat.
  • By the exhaled air.
  • By vaginal fluids.

The odor given off is quite unpleasant, as it tends to resemble rotten fish.

Although this unpleasant condition does not affect the growth of the sufferer or psychomotor development, it is uncomfortable enough for people who suffer from trimethylaminuria due to the foul smell, which can severely affect their self-esteem, creating anxiety and stress, and depression.

This disease does not have a specific treatment, so the fundamental recommendations are based on:

  • Avoid consuming foods that contain choline, carnitine, nitrogen, and sulfur, to mitigate body odor, and these include (legumes, egg white, shellfish, and bluefish).
  • Shower at least two times a day.
  • Change clothes after every shower is taken.
  • Use neutral deodorants.

The Spanish Association of Pediatrics states that trimethylaminuria has an estimated incidence of 1 case every 40,000. 1% could be a carrier of this condition. Only 4 cases of this disease have been described [2].

Fishy odor on the genitals from bacterial vaginosis

On the other hand, another reason related to urine with a fishy smell is a vaginal infection known as bacterial vaginosis. Although this characteristic smell comes from vaginal discharge, it is easily confused with urine.

Bacterial vaginosis (BV) is a vaginal infection caused by an imbalance of healthy bacteria typically found in the vagina. The most common of these is known as Gardnerella Vaginalis.

There are factors related to the presence of this vaginal infection that modifies the normal pH of the vagina. These include:

  • Vaginal deodorants.
  • Use of the IUD or intrauterine device.
  • Vaginal douches
  • Multiple sexual partners.
  • Have a new sexual partner.

In addition to this, any woman with bacterial vaginosis has a greater chance of contracting a sexually transmitted disease.

The presence of this condition tends to be asymptomatic in some cases. However, in others it is likely to exist:

  • Fishy-smelling vaginal discharge that may be thought to come from urine.
  • The smell tends to be even more noticeable after sexual intercourse.
  • Heavy vaginal discharge.
  • Whitish, grayish, or greenish discharge.
  • Sparkling flow.
  • Burning when urinating.

If bacterial vaginosis occurs during pregnancy, the chances of a premature pregnancy increase.

Once the symptoms have been detected in case they are present, do not hesitate to go to the doctor for the indication of treatment, which may include:

  • Antibiotics in oral tablets.
  • Antibiotic gel or cream for local application in the vagina.
  • The most common to use are metronidazole and clindamycin.
  • In the case of a stable sexual partner, this will not require treatment.

Likewise, it is essential to comply with the medical recommendations:

  • Finish the treatment for the indicated days.
  • Refrain from having sexual intercourse during treatment.
  • The use of probiotics can be helpful for this infection.

Smelly urine: causes

Other factors can cause changes in the smell of urine and make it unpleasant. These are the following:


Consumption of some vitamin supplements may be responsible for changing the typical smell of urine. This occurs after the consumption of:

  • Vitamin D.
  • Vitamin B6.
  • Football.

The foul smell in the urine tends to be greater in people who have not consumed enough water during the day.

The pregnancy

The transformations that the woman’s body undergoes during pregnancy are reason enough to modify the smell of urine. This occurs because pregnancy makes the urine even more concentrated, and it will worsen if the woman does not increase her daily water intake.

If you are pregnant and you have noticed that your urine has changed in smell, increase water consumption, and go immediately to the doctor if this does not improve.


The daily diet is reason enough for the urine to undergo modifications, the pungent smell in the urine can occur after the consumption of asparagus.

Asparagus contains a component called asparagusic acid, natural sulfur in this vegetable, which, although not harmful to health, allows the smell of urine to be changed.

In this case, the odor tends to disappear after approximately 12 hours.

Other causes that can cause a change in the typical smell of urine are:

  • Dehydration: a deficit in daily water consumption can proportionally change the typical characteristics of urine, causing it to have a more pungent odor and a more concentrated color.
  • Urinary Tract Infections: The urinary tract can be affected by bacteria, causing what is known as a urinary tract infection or UTI. This makes the urine smell more potent and much more concentrated.
  • Diabetes mellitus: this is another reason why urine changes color. In this case, the urine turns to a sweet smell, which occurs when diabetes mellitus is not appropriately treated.

Habits for a healthy bladder

Some healthy habits will allow you to have a healthy bladder free of infections and changes in its characteristics. These include:

  1. It would be best if you urinated 5 to 7 times a day.
  2. It is beneficial to get up once a night to urinate.
  3. Do not make involuntary urination. Urinate when necessary.
  4. We are not holding back urine.
  5. It is taking time to urinate.
  6. Maintain proper hygiene in the intimate area.
  7. Avoid intimate products with a smell.
  8. Consume water constantly, at least 2 liters daily.
  9. Avoid wearing tight underwear.

Go immediately to the doctor if you notice that your urine smells fishy or has changed its color and typical smell. The specialist will indicate the appropriate treatment for each condition to be treated.

This article is merely informative. At FastlyHeal .com, we do not have the power to prescribe medical treatments or make any diagnosis. We invite you to see a doctor if you present any condition or discomfort.

If you want to read more articles similar to Urine with a fishy smell: causes and treatment, we recommend that you enter our Kidneys and urinary system category.

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