Ketones are a type of acid your body produces when it needs to break down body fat for energy. Trace amounts of ketones in your urine aren’t usually a cause for concern, but high levels can indicate a serious medical issue.
Ketones in your urine (ketonuria) can be a sign of a few different health problems, medical conditions, or changes in your body.
People with medical conditions like diabetes are prone to having ketones in their urine, but ketonuria can also occur during pregnancy and with certain diet changes.
This article will explore what ketones are, what it means when they appear in your urine, and how high your ketone levels need to get to signal a serious problem.
Ketones are a type of acid your body makes when there isn’t enough glucose in your blood to meet your energy needs. Your body needs a constant supply of energy just to maintain your basic functions, and glucose is the main form of this energy.
When glucose supplies drop too low, either from your diet or a medical condition like diabetes, your body might turn to other sources — like body fat — for energy.
Ketones are the byproduct of your body using fat in place of glucose for energy. Small amounts of this acid, sometimes called trace ketones, are pretty normal — especially after periods of sleep or fasting. We all have times when our glucose levels can dip a little and our body turns to alternative energy sources.
However, too much of this acid produced during longer periods of fat metabolism can change the chemical balance of your body. Your body needs a balance of acids and bases, measured by your pH level. When ketone levels rise too much, your body can become too acidic.
What is pH?
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Too much acid in your body will lower your pH level (acidemia), and too little acid or too much of an alkaline compound will increase your pH level above this range (alkalemia).
When your pH levels go outside the normal ranges and your body can’t compensate, these changes can cause breathing and digestion problems, or even result in critical illness and death.
Ketone levels can rise to abnormally high levels for a number of reasons. Since ketones are produced when your body breaks down fat for energy, ketonuria can occur in periods of long-term fasting or when following a keto (low carb, high fat) diet.
Certain medical conditions, especially diabetes, can also increase your risk of burning fat for energy.
When you have diabetes, your body is lacking insulin or has stopped responding to the insulin you’re making. Insulin is the hormone that moves glucose from your bloodstream into your cells where it is used for energy.
If you have diabetes, your body uses insulin ineffectively or doesn’t produce enough insulin to effectively move glucose into your cells. Glucose then builds up in your blood and your cells begin to starve. This causes your cells to turn to body fat for energy, and your body will produce more ketones to burn fat, a process known as ketosis.
When ketone levels are moderate, ketosis isn’t particularly harmful, but when ketone levels rise too much or ketosis goes on for long periods of time, ketoacidosis can occur. Ketosis on its own
Ketosis and ketoacidosis: What are the symptoms?
If the ketone levels in your body rise too much, you can experience a range of symptoms that include:
- nausea
- abdominal pain
- fatigue
- increased thirst
- dry mouth
- flushed skin
- difficulty breathing
- a fruity smell to your breath
- confusion
These symptoms can be mild or barely noticeable, but intense confusion, thirst, difficulty breathing, and other severe symptoms can mean you’re experiencing ketoacidosis.
When ketone levels rise too high, your body can reach a toxic, even fatal level of acidity.
Some conditions or events outside of diabetes that can cause the ketone levels in your body to rise include:
- vomiting
- diarrhea
- alcoholism or heavy alcohol consumption
- eating disorders
- starvation
- low carbohydrate diets
- certain digestive diseases
- intense exercise
- pregnancy
A note on restrictive diets
If you’re preoccupied with food or your weight, feel guilt about food choices, or engage in restrictive diets, consider reaching out for support. These behaviors may indicate a disordered relationship with food or an eating disorder.
Disordered eating and eating disorders can affect anyone, regardless of gender identity, race, age, socioeconomic status, or other identities.
They can be caused by any combination of biological, social, cultural, and environmental factors — not just by exposure to diet culture.
Consider speaking with a healthcare professional, or try chatting, calling, or texting anonymously with trained volunteers at the National Eating Disorders Association helpline for free.
Most people don’t need to check their ketone levels regularly. Ketones can appear in your urine if you’re having routine urine testing done. A doctor may also suggest testing your urine for ketones if you’re at a high risk of ketoacidosis because of diabetes or another condition.
Dipstick testing is one way to check your urine for ketones. These tests use a plastic strip that changes color when exposed to ketones. These tests are able to check for the presence of a certain ketone range but won’t give you an exact measurement of your ketone levels.
You can buy ketone test kits in many retail stores or pharmacies.
If you have a condition or symptoms that make a more exact ketone count necessary, a doctor may take a larger sample of urine and send it to a laboratory for testing. These tests may refer to the number of ketones in your urine as small, moderate, or high, or they may provide specific measurements.
Ketone levels in your urine and what they mean
Trace ketone levels or even a moderate level of ketosis might not be bad for you. Generally, a reading of 2 or more on a simple urine ketone test is a cause for concern. The ranges below offer more specific information about your ketone levels and what they mean.
- Normal level: A ketone level at or below 0.6 millimoles per liter (mmol/L) in your urine or blood is considered a normal amount or trace amount.
- Low to moderate level: A ketone level of 0.6 mmol/L to 1.5 mmol/L is considered a low to moderate amount and may increase your risk of ketoacidosis.
- High level: A ketone level of 1.6 to 2.9 mmol/L is considered a high level of ketones and means you need to see a healthcare professional, especially if you have diabetes.
- Medical emergency: A ketone level of 3 mmol/L is a high reading and is considered a medical emergency. Contact 911 or local emergency services if your ketones reach this level.
Discover more about Type 2 Diabetes
Managing your diet and blood glucose levels will help you maintain a safe level of ketones. If you have diabetes, checking your blood glucose levels regularly and treating high blood glucose levels with insulin and other medications as directed by a doctor will help you manage your ketone levels.
In most cases, if you have diabetes, a blood glucose level above 240 milligrams per deciliter (mg/dL) indicates a need for checking your blood, breath, or urine for ketones.
Other steps you can take to keep your ketone levels in a healthy range include:
- drinking enough water
- avoiding excessive exercise
- carefully managing diabetes when you’re sick with a cold or infection
Can a UTI cause trace ketones in urine?
Ketones can appear in your urine for many reasons. Infections are one cause, and urinary tract infections (UTIs) in particular may cause a spike in your urine ketone level.
Can dehydration cause trace ketones in urine?
Dehydration and starvation can increase the level of ketones in your blood or urine.
Can pregnancy cause trace ketones in urine?
Ketonuria is a common finding in pregnancy, affecting about 1 in 5 people who are pregnant. Ketonuria in pregnancy is caused by the metabolism of fats, and it’s most common in the middle of pregnancy, in the 16- to 28-week range.
Can certain foods cause trace ketones in urine?
A low carb or ketogenic diet that emphasizes protein consumption over eating carbohydrates and sugars can lead to nutritional ketosis.
To a certain extent, nutritional ketosis can be beneficial for weight loss. However, long-term starvation or calorie restriction, or overconsumption of things like alcohol, can increase your ketones to dangerous levels.
Most people have tiny, or trace, amounts of ketones in their urine. This is particularly true when you haven’t eaten for a while, like first thing in the morning when you wake up.
If you have diabetes or other conditions that affect your metabolism, a doctor may suggest that you check your ketone levels from time to time. Illness, intense activity, and high blood sugar levels can increase your ketone levels and make your body dangerously acidic.
Talk with a doctor or medical professional if you want to check your ketone levels, or if regular ketone monitoring is important for you. Ketone testing can be done to some extent quickly and easily at home by using ketone test kits available at many stores and pharmacies.