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Trimethylaminuria (TMAU) - Fishy Body Odor Causes and Treatment

  • Date: 2014/03/25 (Rev. 2017/03/02)
  • Disabled World - Disabled World
  • Synopsis : Trimethylaminuria or TMAU is a rare metabolic disorder also known as fish odor syndrome or fish malodor syndrome that creates a fishy body smell.

Main Document

Trimethylaminuria (TMAU) can affect men, women, and children, from newborns to the elderly in most countries around the world.

When an individual tends to give off a strong fishy smelling body odor it can caused by a compound called trimethylamine or TMAU. TMAU is a rare metabolic disorder also known as fish odor syndrome or fish malodor syndrome.

Trimethylaminuria (TMAU) is a rare genetic disorder in which the human body's metabolic processes fail to alter the chemical trimethylamine, symptoms are often present from birth. Trimethylamine is notable for its unpleasant fishy smell. It is the chemical that gives rotten fish a bad smell. When the normal metabolic process fails, trimethylamine accumulates in the body, and its odor is detected in the person's sweat, urine and breath.

TMAU causes a defect in the normal production of the enzyme Flavin containing monooxygenase 3. Trimethylamine builds up in the body of patients with trimethylaminuria. The trimethylamine gets released in the person's sweat, urine, reproductive fluids, and breath, giving off a strong fishy or body odor.

People with trimethylaminuria end up with a build up of trimethylamine, which is then released through their sweat, urine, reproductive fluids, and breath. Many people who suffer from trimethylaminuria, known colloquially as "fish malodor syndrome," also suffer from depression as a result of disruptions trimethylaminuria can cause to social life, relationships, or career.

TMAU is listed as a "rare disease" by the Office of Rare Diseases (ORD) of the National Institutes of Health (NIH). This means that TMAU, or a subtype of TMAU, affects less than 200,000 people in the US population.

The condition seems to be more common in women than men, for unknown reasons. According to the National Human Genome Research Institute, scientists believe that it could be due to the higher levels of female sex hormones such as progesterone and/or estrogen, aggravate symptoms.

Currently, there is no cure and treatment options are limited for TMAU. It is possible for some people with this condition to live relatively normal, healthy lives without the fear of being shunned because of their unpleasant odor. Getting tested is an important first step as a simple urine test will give you the answer; a blood test is available to provide genetic analysis. The prominent enzyme responsible for TMA N-oxygenation is the FMO3 gene.

Ways that may help eliminate the fishy odor include avoiding foods containing trimethylamine and its precursors like:

  • Eggs
  • Liver
  • Peas
  • Beans
  • Kidney
  • Peanuts
  • Broccoli
  • Cabbage
  • Cauliflower
  • Soy products
  • Brussel sprouts
  • Milk from wheat-fed cows,
  • Lecithin and lecithin-containing fish oil supplements
  • Seafood (Freshwater fish have lower levels of trimethylamine N-oxide)

Also Try:

  • Using body soaps with a moderate pH, between 5.5 and 6.5
  • Avoiding factors that promote sweating, such as exercise, stress, and emotional upsets.
  • Taking low doses of antibiotics to reduce the amount of bacteria like trimethylamine in the gut
  • Taking activated charcoal or other supplements to decrease the concentration of free trimethylamine in the urine
  • Taking riboflavin (vitamin B2) supplements to enhance FMO3 enzyme activity. Recommended intake is 30 to 40mg taken 3 to 5 times per day with food.

TMAU Testing

The only test for trimethylaminuria at this time is a urine test for elevated levels of trimethylamine.

A similar test can be used to identify carriers of this condition - those individuals who carry one copy of a mutated gene but do not have symptoms. In this case, the person would be given a high dose of choline (one of the precursors of trimethylamine) and then have their urine tested for elevated levels of trimethylamine.

Dealing with trimethylamuinuria can be emotionally painful and isolating, but therapy and appropriate medical treatment can prove really helpful in alleviating some of its symptoms and repercussions.


US Foundation - The Trimethylaminuria Foundation is a 501 3 (C) non-profit corporation. The address is P.O. BOX 3361, Grand Central Station, New York, NY, 10163. Telephone: 212-300-4168.

Australian Foundation - A non-profit, charitable foundation with tax free status and tax deductibility against income for donors. 8 Ingram Street, Kensington, NSW 2033, AUSTRALIA Phone: 61 2 9663 0431

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