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Can Hypothyroidism Be The Cause of Sweet-smelling Urine?

The smell and appearance of your urine can say a lot about your health. So finding a change in your urine can be a cause of concern. One such change is having urine that smells sweet.

Sweet-smelling urine can have a variety of causes. There are a few diseases that are associated with this type of urine. If you have a chronic disease, it’s natural to assume if your urine is related to that disease. Such a common chronic disease is hypothyroidism.

So, you’re not alone if you are wondering, does hypothyroidism cause sweet-smelling urine?

Hypothyroidism by itself doesn’t cause sweet-smelling urine. However, it does increase the risk of diabetes mellitus. And this is the most common cause of sweet-smelling urine. But that’s not the only cause. In fact, sweet-smelling urine can be due to Urinary tract infection, Maple syrup urine disease, or even dietary changes.

Well, to know more about it, just read through the next segments.

Table of Content

Hypothyroidism Sweet Smelling Urine

To answer your question, no, hypothyroidism doesn’t cause sweet-smelling urine directly.

This type of sweet-smelling urine is mostly due to diabetes. The fruity smell here is mostly due to ketones. Ketones are chemicals that your body produces while making energy.


The presence of ketone bodies in your urine is called ketonuria. And hypothyroidism can’t directly cause ketonuria. So it’s highly unlikely that your hypothyroidism is the cause of the sweet-smelling urine.

However, hypothyroidism does slow down the metabolism.

And this can increase the risk of diabetes mellitus. Diabetes mellitus can be the cause of sweet-smelling urine. But hypothyroidism by itself doesn’t cause sweet-smelling urine.

Sudden Onset of Sweet-Smelling Urine: Why?

If hypothyroidism is the cause of your sweet-smelling urine, then what is the cause? If this sweet-smelling urine occurs only once, then it’s no cause for concern. However, if this happens more than once, then it is likely due to a medical condition.

Below are some of the conditions which can cause sweet-smelling urine:

Diabetes Mellitus

Diabetes mellitus is a common disease that affects nearly 8-10% of the adult population. This is the 7th leading cause of death worldwide. Recent data shows that this disease is on the rise. As time goes, more and more people will be affected by this condition.

We have made noteworthy advancements in medical science. Yet, scientists have found no way to completely cure this disease. However, with proper medications and lifestyle changes, it is possible to control diabetes.

This disease is among the most common causes of sweet-smelling urine. 


The word ‘diabetes Mellitus’ has Greek and Latin origins. The Greek word ‘diabetes’ means siphon. It was used to refer to excessive urination. And the Latin word ‘Mellitus’ means sweet. So, sweet urine is literally the meaning of the disease. 

Types of Diabetes

There are two types of diabetes. Type I diabetes: This occurs at a young age. In this case, there is a total loss of the cells which make insulin. So, insulin has to be administered from outside.

Type II diabetes: This type occurs at an older age. Here, the cells slowly respond less to obesity. This disease is associated with obesity, old age, a sedentary lifestyle, etc.

Most people who develop diabetes have this type. Oral drugs are normally enough to treat this disease. However, insulin is also needed sometimes.

Why This Occurs?

So, how does urine become sweet in diabetes? The answer lies in your body’s normal metabolism. We all need the energy to survive. We need this energy to maintain our body’s function. Without proper energy, the cells of our bodies will die within a matter of hours.

We get this energy from food. And among the main types of food, carbohydrates provide the most energy. 

And glucose is the simplest form of carbohydrate. In fact, most carbohydrates we eat are converted into glucose.

This glucose moves in our blood. And blood flows to almost every cell. And whenever the cells need glucose, they can take it from the blood. However, the levels of glucose have to be nearly constant in our blood.

So, our body has a mechanism to control this blood glucose. This is done through an abdominal organ called the pancreas.

The pancreas releases a hormone called insulin. This insulin then goes to the blood and to the different cells. Insulin acts as a gatekeeper and allows glucose to enter into the different cells. Without insulin, glucose can’t enter these cells.

When we eat, our stomach absorbs all the glucose. 

So, insulin is also released. This causes glucose to enter into different cells. The blood glucose rises sharply but falls as the cells take the glucose in.

When we are starving, our insulin level falls. Then, the muscles can release stored glucose. The liver can also make new glucose. Thus glucose levels are maintained.

However, in diabetes mellitus, the insulin can’t function properly. So, glucose can’t enter the cells. All of the glucose that your stomach absorbs stays in your blood. So, your blood glucose levels skyrocket.

Your kidney tries to get rid of this excess glucose. So, the glucose-filled urine is sweet.

This forces many metabolic changes in your body cells as well. That’s because even if glucose can’t enter the cells, they have to survive. So the cells use other substances to make energy. 

Cells use other pathways to make energy that doesn’t use glucose. 

One such pathway is the ketogenic pathway. Here, the cells break down fat to make energy. Ketone bodies are the by-products of this process.

Diabetic patients have elevated levels of ketone bodies in their blood. These excessive ketone bodies have to be eliminated by the kidneys. And acetone, which is a ketone body, has a fruity smell. This is a cause of sweet-smelling urine and sweet breath.

Sometimes, the levels of ketones can rise excessively. Such a condition is called diabetic ketoacidosis. Here, the patient faints and has sweet-smelling breath and urine.

Sweet-Smelling Urine: Pregnancy

One type of diabetes mellitus is gestational diabetes mellitus. It is diabetes that occurs among mothers without a previous diagnosis of diabetes.

During pregnancy, several hormonal changes occur in the body. These hormones can decrease the activity of insulin on cells. So, the mother might become diabetic.

Thus this condition can cause sweet-smelling urine during pregnancy,

Other Signs and Symptoms:

There are other signs and symptoms of diabetes as well. So, if you have these along with sweet-smelling urine, then it’s likely what’s affecting you:

  • Feeling very thirsty throughout the day despite drinking enough water
  • Peeing more than usual
  • Unexplained weight loss
  • Fatigue
  • Excessive hunger despite eating

If you experience these, it’s best to see a doctor as soon as possible. They can diagnose whether you have diabetes or not. 

Early treatment and proper diet and discipline can prevent most complications of diabetes.

Urinary Tract Infection

UTI can be the cause of sweet-smelling urine as well. This is a disease that affects mainly women. Almost 10% of the adult women population suffers from this disease every year.


UTI or urinary tract infection means an infection in any part of the urinary tract. If it affects the kidneys, it’s an upper urinary tract infection/kidney infection. And if it affects the bladder or the urethra, it’s known as a lower urinary tract infection.

Causes of UTI

Different types of bacteria are the main culprits in this case. But fungus can be the cause too in rare cases. The bacteria involved are:

  • Escherichia coli
  • Staphylococcus saprophyticus
  • Proteus mirabilis
  • Klebsiella species
  • Pseudomonas species
  • Haemophilus species
  • Yersinia species
  • Enterococci

Almost 90% of the UTIs which happen in the community are due to E. coli. This bacteria is a part of our normal flora. This means that it’s present in the normal human large intestines. These have beneficial effects on the intestines. They are excreted in the feces too.

However, if they get to the urinary tract, they can cause an infection there.

They can produce various compounds when they cause an infection inside the urinary tract. These compounds mixed with urine can sometimes give a sweet smell.

How Will You Know if You Have UTI?

What other symptoms will you have if you have a UTI? Below are some of the symptoms you should look out for:

  • Excessive urination
  • Pain and burning sensation during peeing
  • After urinating, having a sense that the bladder hasn’t been emptied
  • Lower abdominal pain
  • Fever
  • Cloudy or hazy urine

If you have these symptoms, then it is likely that you have a UTI. There are several antibiotics that are used for this. Your doctor can provide you with the right one.

Maple Syrup Urine Disease

This is a rare genetic disease. As the name implies, this causes urine that smells like maple syrup.

The inheritance of this disease is autosomal recessive. This means that both copies of genes have to be defective. We all have two copies of every chromosome. If both of those have MSUD defects, then the disease will occur. A single gene defect will not cause the disease.

What Happens in This Condition?

We all know that protein is what builds our bodies. And the building block of protein is amino acids. You can think of amino acids as lego blocks and proteins as large structures made out of the blocks.

We get our daily requirement of amino acids from the food we eat. At the same time, the used-up proteins are broken down into amino acids too. These amino acids need to be broken down as well. Otherwise, amounts of particular amino acids might increase too much.

There are several enzymes that break down different types of amino acids. In MSUD, one of those enzymes isn’t produced. So, the amino leucine, isoleucine, and valine can’t be broken down.

These are ketogenic amino acids. These amino acids and their by-products accumulate. The body tries to get rid of these through the urine. One of these compounds is sotolone. This chemical has a strong sweet smell. This is the reason why urine smells sweet in this disease.

How to Know if You Have Msud?

This disease is diagnosed in childhood. So, if you never had sweet-smelling urine previously, it’s highly unlikely you have this disease. Other signs and symptoms include:

  • Convulsions
  • Diarrhea
  • Anemia
  • Weakness
  • Lethargy and easy fatigue
  • Mood swings and behavioral changes, etc.

These symptoms can occur in other diseases as well. Measuring the levels of particular amino acids in the blood can give a proper diagnosis. So, it’s best to see your doctor.


Particular types of food can also make your urine smell sweet. Some foods naturally contain some particular chemical compounds.

These chemicals are not broken down and pass out of the urine. These may make the urine smell sweet.

One such compound is sotolon, the same compound in maple syrup urine disease. This compound is found in fenugreek, rum, molasses, etc. If you consume these foods in high amounts, your urine might smell sweet.

Sweet-Smelling Urine: Keto

Another reason for sweet-smelling urine might be the keto diet. When you go on a keto diet, your keto acid levels might increase. Such a condition is called ketosis.

If the ketone body levels in the blood get too high, some of them might be excreted in the urine. This is what might cause the sweet-smelling urine.


Can hypothyroidism cause urine odor?

Hypothyroidism normally doesn’t cause any urine odor. But some patients have complained of chemical-smelling urine. Sometimes, hypothyroid urine might smell like fish.

Does thyroid affect urine smell?

Thyroid hormone generally has no effect on the urine smell. However, there may be a chemical smell or a fishy smell rarely.

Does your urine smell sweet with diabetes?

Yes, if you have diabetes, your urine might smell sweet. Excess sugar passes into the urine in diabetes. There’s also the generation of ketone bodies which are excreted through urine. This can make the urine smell sweet.

What does pre-diabetic urine smell like?

Sometimes, sweet-smelling urine can occur in pre-diabetic conditions. However, many patients show no smell in urine. It’s best to see a doctor if you suspect you have diabetes.

Can you see sugar in urine?

There are various laboratory tests that can figure out if you have sugar in your urine. Nowadays, dipstick tests are widely available. You can easily use these at home to determine if you have sugar in your urine.


Hypothyroidism sweet-smelling urine is unlikely to happen. If you have sweet-smelling urine, then it’s likely due to diabetes or a change in your diet.

You don’t have to worry if you’ve had sweet-smelling urine only once or twice. But, if you have this sweet-smelling urine constantly, then it’s a cause of concern. It’s best to see a doctor to be safe.

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