Why Does My Urine Smell Sweet?

Sweet-smelling urine can be a sign of an underlying medical condition or infection. Diabetes, urinary tract infections (UTIs), liver disease, and metabolic disorders can make urine smell sweet.

Dehydration, very low-carb diets, vitamin supplements, and some medications can also give urine a sweet scent.

In people with type 1 diabetes, sweet-smelling urine is a sign of a potentially life-threatening complication called diabetic ketoacidosis (DKA).

Reasons Why Your Urine Smells Sweet

Changes in the odor, color, and appearance of urine can happen for many reasons, and it's not necessarily a sign of a problem. However, sweet-smelling urine is almost always a sign of a medical condition.

Some of these conditions will get better with treatment, but others can be fatal. If you notice your pee smells sweet, tell your healthcare provider.

Hyperglycemia and Diabetes

Fruity-smelling urine is sometimes the first sign of diabetes. High blood sugar (hyperglycemia) is common in people with undiagnosed diabetes or poorly controlled diabetes.

High levels of sugar (glucose) in the urine can make it smell sweet or like fruity cereal. There are also other signs of high blood sugar, including:

• Excessive thirst
• Frequent urination
• Feeling hungry even after eating
• Feeling tired
• Having blurred vision

Diabetic Ketoacidosis (DKA)

Diabetic ketoacidosis (DKA) is a very serious, even life-threatening, condition where chemicals called ketones build up in the blood. Too many ketones make the blood too acidic.

The cells of people with diabetes have a hard time receiving the glucose they need for energy. This can be because there is not enough insulin in the body, insulin resistance has developed, or there is not enough sugar in the blood (hypoglycemia). This can happen if a person takes too much insulin from insulin injections or is caused by diabetes medications.

If the cells cannot access glucose, they will start to break down fat for energy. The chemicals that are made when fat is broken down are called ketones.

When ketones build up, they can poison the body. This condition is called diabetic ketoacidosis or just DKA. People with both type 1 and type 2 diabetes can go into DKA, but it's more common if someone has undiagnosed or poorly controlled diabetes.

DKA can come on slowly or quickly. Sometimes, DKA comes on in just a few hours, especially if a person is vomiting.

Early signs of DKA include:

• Thirst
• Very dry mouth
• High blood sugar levels
• High ketone levels in the urine

As DKA progresses, you may experience:

• Nausea, vomiting, or abdominal pain
• Constantly feeling tired
• Dry or flushed skin
• Breath that has a fruity odor
• Trouble breathing
• Difficulty paying attention
• Confusion

If DKA is not treated, a person can go into a coma or die.

Urinary Tract Infections (UTIs)

Urinary tract infections (UTIs) happen when bacteria such as E. coli get into the kidneys, ureters, bladder, and/or urethra.

UTIs are common, especially in females who have a shorter urethral length and can have post-menopausal changes in the vagina.

UTIs often cause urine that's foul-smelling, but they can also cause sweet-smelling urine.

Other symptoms of UTIs include:

• Frequent and urgent need to urinate
• Pain when urinating
• Nighttime urination
• Urine leakage
• Blood in urine
• Changes in the odor of urine (especially foul-smelling)
• Cloudy urine
• Pain in the side, abdomen, lower back, penis, or pelvic area
• Pressure in the lower pelvis
• Pain during sex
• Temperature over 100 F and chills
• Fatigue
• Vomiting
• Mental changes or confusion

Foetor Hepaticus

Foetor hepaticus is the smelly breath of people with liver disease. It's also called the “breath of the dead" and happens when compounds from liver damage get into the lungs. It can also make the urine smell unusual.

Maple Syrup Urine Disease

Maple syrup urine disease (branched-chain ketoaciduria) is an inherited disorder that causes a newborn baby to be unable to process amino acids properly.

Maple syrup urine disease occurs in one in 185,000 infants worldwide. The most common and most severe form of maple syrup urine disease is the classic type. It is usually noticed shortly after birth.

Other forms of the disease can show up in later infancy and childhood. Though less severe, they still require medical attention.

The symptoms of maple syrup urine disease include:

• Sweet-smelling urine
• Poor feeding
• Vomiting
• Lack of energy (lethargy)
• Abnormal movements
• Delayed development

If maple syrup urine disease is not treated, it can cause seizures, coma, and death. Talk to your pediatrician if your baby's urine smells sweet.

Other Causes

There may also be a less serious reason your urine smells sweet. These include the following:

• Dehydration makes urine more concentrated and smell stronger. Often described as ammonia-like, it can also smell sweet. If your urine smells sweet or strong and is a darker shade of amber, drink more water. 
• Keto and other diets that are very low in carbohydrates can make your urine smell unusual or fruity due to nutritional ketosis.
• Medications can also cause sweet-smelling urine, but this is commonly due to a side effect of high blood sugar. Drugs that may cause high blood sugar include corticosteroids, beta-blockers, diuretics, statins, some antibiotics, oral contraceptives, and antipsychotics.
• Supplements containing vitamin B6 supplements, like multivitamins, may give urine a sweet or unusual odor. The herb fenugreek, often taken to boost breastmilk production, can make urine smell like maple syrup.
• Yeast infections can give your urine an unusual odor as well. Often described as yeasty, it can sometimes make urine smell sweet.

Diagnosing Sweet-Smelling Urine

Your healthcare provider can test your urine (urinalysis) to determine what is causing the smell. They can also do other tests, such as:

• Blood tests
• Imaging
• Genetic analysis

Treatment

Each medical condition that can cause sweet-smelling urine has its own treatment protocol.

• Type 1 diabetes: People will require insulin through injection or pump.
• Type 2 diabetes or gestational diabetes: People might be able to manage through lifestyle changes (like diet and physical activity), but they may also need insulin or medications to control the condition.
• Diabetic ketoacidosis: DKA is a medical emergency that always needs to be treated in the hospital. People with DKA need insulin, fluids, and other treatments to help their bodies recover.
• Urinary tract infections: UTIs are treated with antibiotics. The antibiotic prescribed will depend on which bacteria is causing the infection. There are also medications that can help ease UTI symptoms while you're waiting for the antibiotics to work.
• Foeter hepaticus: Medications and liver-friendly lifestyle changes, such as a nutritious diet and avoiding alcohol, are common ways to treat this condition. However, liver damage cannot always be reversed.
• Maple syrup urine disease: This condition cannot be cured. Treatment is lifelong and includes following a protein-restricted diet and taking supplements. Metabolic crises that can result from this condition require immediate medical attention.

Prevention

To avoid having sweet-smelling urine, you'll need to prevent or treat the conditions that cause it.

Type 1 diabetes: This autoimmune disorder cannot be prevented. It is usually diagnosed in young people but can develop at any age. People with type 1 diabetes need to take insulin throughout their lives.

Type 2 diabetes: This condition usually develops later in life. The symptoms and side effects of type 2 diabetes can often be prevented by making lifestyle changes or taking medication.

DKA: Managing diabetes is the first step in preventing DKA. If you get sick (such as with a cold or flu), checking and monitoring ketone levels at home using test strips can alert you to early warning signs of DKA. Avoiding exercising if your ketones and blood sugar levels are high can also help prevent DKA. If your ketone levels are high, you need to contact your healthcare provider—especially if you are also vomiting.

UTIs: There are numerous ways to help prevent UTIs:

• Drink plenty of fluid to help flush bacteria from the urinary tract.
• Practice good hygiene, such as wiping from front to back, hand-washing, and changing menstrual products frequently.
• Limit alcohol, citrus juices, caffeinated drinks, and spicy foods, which can irritate the bladder.
• Urinate before and after sex.
• Wash the genital area with warm water before sex but do not douche.
• Avoid genital deodorants.
• Change birth control methods (diaphragms and/or spermicide can increase the risk of UTIs).
• Use a water-based lubricant during sex.
• Wear cotton underwear and avoid tight clothing.
• Consider cranberry supplementation.
• Consider taking low-dose antibiotics to prevent infection if you get frequent UTIs.

Foeter hepaticus: Steps that could help prevent liver damage include:

• Exercise regularly.
• Maintain a healthy weight.
• Avoid alcohol or other substances that are toxic to the liver.
• Take medications only as necessary. Check the side effects, and make sure they will not interact with other medications or supplements you take (including over-the-counter medicines).
• Keep up-to-date with vaccinations.
• Practice safety while traveling concerning food, drink, and local health threats.
• Make sure proper safety guidelines are followed when getting tattoos or piercings.
• Practice safer sex (such as condom use) for STI prevention.

Maple syrup urine disease: Since this is a recessive genetic disorder, parents can have genetic testing done before conception and/or on the zygote/embryo/fetus after conception to check for the condition. A person will get the condition if they receive an affected gene from both parents.

If both parents have one affected gene and one unaffected gene (carriers), their chances of having a child with the condition are 25% for each pregnancy. The chance of their child being a carrier is 50%, and the chance of their child not receiving an affected gene is 25%.

Summary

Sweet-smelling urine can be caused by different medical conditions. Some conditions that cause sweet-smelling urine are easy to manage, but others can be life-threatening without immediate medical treatment. If your urine smells sweet, contact your healthcare provider.