Elizabeth Marsh's Blog
May 2, 2025
TMAU – the Rare Invisible Disability
Living with Trimethylaminuria (TMAU)
Trimethylaminuria (TMAU), often referred to as Fish Odor Syndrome, is a rare metabolic disorder that causes the body to be unable to properly break down trimethylamine (TMA), a compound with a strong, fishy smell. For those affected, this condition can lead to significant emotional and social challenges.
Although TMAU is commonly referred to as fish odour syndrome, the odour can manifest as fecal, garbage or other strong odours depending on what is being digested in the gut. This disorder makes food the enemy.
What Is Trimethylaminuria?
TMAU is caused by a deficiency in an enzyme called flavin-containing monooxygenase 3 (FMO3). This enzyme is responsible for breaking down trimethylamine, which is produced during the digestion of certain foods such as eggs, liver, legumes, and some seafood.
In individuals with TMAU, trimethylamine builds up in the body and is released through sweat, breath, and urine—resulting in a strong body odor often compared to rotting fish, garbage, or eggs. The intensity of the odor can vary from day to day and person to person.
Causes and Inheritance
Most cases of TMAU are inherited in an autosomal recessive pattern, meaning both parents must pass on the defective gene. Some people can also have a secondary form of TMAU, where external factors like diet, liver damage, antibiotic abuse or hormonal changes (e.g., menstruation, stress) temporarily reduce FMO3 activity.
Symptoms and Impact
The main symptom is a persistent and uncontrollable body odor that perfumes and good hygiene cannot mask. While TMAU doesn't cause physical pain or organ damage, the psychological impact can be severe. Many individuals with TMAU experience:
• Social isolation
• Anxiety or depression
• Low self-esteem
• Difficulty maintaining relationships or employment
It’s not uncommon for sufferers to feel misunderstood or judged, especially since TMAU is often misdiagnosed or dismissed by medical professionals.
Diagnosis
Diagnosing TMAU typically involves:
• Urine tests to measure levels of trimethylamine and its oxidized form.
• Genetic testing to identify mutations in the FMO3 gene.
However, diagnosis can be tricky, especially in mild or intermittent cases, and many people go years without answers.
Managing TMAU
There is no known cure for TMAU, but lifestyle changes can help reduce symptoms. These include:
• Dietary changes: Avoiding foods high in choline, lecithin, and carnitine, such as eggs, liver, beans, certain fish, and some cruciferous vegetables.
• Activated charcoal or copper chlorophyllin supplements: These may help absorb or neutralize trimethylamine in the gut.
• Good hygiene practices: While TMA is produced internally, regular washing and using acidic soaps (like low-pH body washes) may help mask or reduce odors.
• Probiotics: To promote a healthy gut microbiome, which may influence TMAU production.
One major problem is that very few healthcare providers are even aware of the disorder which leads to misdiagnoses and despair for those living with the illness.
Mental and Emotional Support
Support groups both online and offline can be a great source of strength for those with TMAU. Talking to others who understand the emotional burden can reduce feelings of isolation and shame. Psychological counselling or therapy may also be helpful for managing anxiety or depression.
Advocating for Awareness
TMAU is more common than once believed, yet it's still rarely talked about. Raising awareness can help reduce stigma, promote earlier diagnoses, and encourage more research into treatments and hopefully a cure.
In Summary
Trimethylaminuria is a challenging condition, not because it causes physical harm, but because of the social and emotional toll it takes.
Greater understanding, empathy, and awareness can make a world of difference.
Read about Lizzy’s harrowing battle with the disorder in the book “Trimethylaminuria (TMAU) – the Rare Invisible Disability. When there are no footprints in the sand.”
Available at the link below:
https://www.amazon.com/author/elizabe...
Also, please remember that “Everyone you meet is fighting a battle you know nothing about. Be Kind. Always.” – Robin Williams
Do you know of, or have you ever encountered someone who you think may have this disorder?
Can you share the encounter with us?
Trimethylaminuria (TMAU), often referred to as Fish Odor Syndrome, is a rare metabolic disorder that causes the body to be unable to properly break down trimethylamine (TMA), a compound with a strong, fishy smell. For those affected, this condition can lead to significant emotional and social challenges.
Although TMAU is commonly referred to as fish odour syndrome, the odour can manifest as fecal, garbage or other strong odours depending on what is being digested in the gut. This disorder makes food the enemy.
What Is Trimethylaminuria?
TMAU is caused by a deficiency in an enzyme called flavin-containing monooxygenase 3 (FMO3). This enzyme is responsible for breaking down trimethylamine, which is produced during the digestion of certain foods such as eggs, liver, legumes, and some seafood.
In individuals with TMAU, trimethylamine builds up in the body and is released through sweat, breath, and urine—resulting in a strong body odor often compared to rotting fish, garbage, or eggs. The intensity of the odor can vary from day to day and person to person.
Causes and Inheritance
Most cases of TMAU are inherited in an autosomal recessive pattern, meaning both parents must pass on the defective gene. Some people can also have a secondary form of TMAU, where external factors like diet, liver damage, antibiotic abuse or hormonal changes (e.g., menstruation, stress) temporarily reduce FMO3 activity.
Symptoms and Impact
The main symptom is a persistent and uncontrollable body odor that perfumes and good hygiene cannot mask. While TMAU doesn't cause physical pain or organ damage, the psychological impact can be severe. Many individuals with TMAU experience:
• Social isolation
• Anxiety or depression
• Low self-esteem
• Difficulty maintaining relationships or employment
It’s not uncommon for sufferers to feel misunderstood or judged, especially since TMAU is often misdiagnosed or dismissed by medical professionals.
Diagnosis
Diagnosing TMAU typically involves:
• Urine tests to measure levels of trimethylamine and its oxidized form.
• Genetic testing to identify mutations in the FMO3 gene.
However, diagnosis can be tricky, especially in mild or intermittent cases, and many people go years without answers.
Managing TMAU
There is no known cure for TMAU, but lifestyle changes can help reduce symptoms. These include:
• Dietary changes: Avoiding foods high in choline, lecithin, and carnitine, such as eggs, liver, beans, certain fish, and some cruciferous vegetables.
• Activated charcoal or copper chlorophyllin supplements: These may help absorb or neutralize trimethylamine in the gut.
• Good hygiene practices: While TMA is produced internally, regular washing and using acidic soaps (like low-pH body washes) may help mask or reduce odors.
• Probiotics: To promote a healthy gut microbiome, which may influence TMAU production.
One major problem is that very few healthcare providers are even aware of the disorder which leads to misdiagnoses and despair for those living with the illness.
Mental and Emotional Support
Support groups both online and offline can be a great source of strength for those with TMAU. Talking to others who understand the emotional burden can reduce feelings of isolation and shame. Psychological counselling or therapy may also be helpful for managing anxiety or depression.
Advocating for Awareness
TMAU is more common than once believed, yet it's still rarely talked about. Raising awareness can help reduce stigma, promote earlier diagnoses, and encourage more research into treatments and hopefully a cure.
In Summary
Trimethylaminuria is a challenging condition, not because it causes physical harm, but because of the social and emotional toll it takes.
Greater understanding, empathy, and awareness can make a world of difference.
Read about Lizzy’s harrowing battle with the disorder in the book “Trimethylaminuria (TMAU) – the Rare Invisible Disability. When there are no footprints in the sand.”
Available at the link below:
https://www.amazon.com/author/elizabe...
Also, please remember that “Everyone you meet is fighting a battle you know nothing about. Be Kind. Always.” – Robin Williams
Do you know of, or have you ever encountered someone who you think may have this disorder?
Can you share the encounter with us?
