What Are Ketones in Urine?

What Are Ketones in Urine?

Ketone bodies, also known as ketones, replace glucose on a low-carb diet. They give your brain and muscles energy and they come with a range of health benefits. When ketone levels are increased, this is known as ketosis. Ketosis is the goal of the ketogenic diet, and many keto dieters want to know when they've reached this metabolic state.

But how do keto dieters know they've finally reached ketosis? Well, one popular way is by testing for ketones in urine. But now, "what are ketones in urine?" you may ask. To find out that and learn more about ketones, read our overview below.

We explain everything there is to know about ketones, how they end up in your urine, and why you should care.

About Ketones

Ketone bodies are three water-soluble molecules that your liver makes from fatty acids. They include:

  • Acetoacetate
  • Beta-hydroxybutyrate
  • Acetone

Ketone production is a normal metabolic process that happens during an overnight fast, prolonged fasting, and starvation [1]. But sometimes, ketone production can go out of control and become dangerous. This is rare, however, and happens in people with alcoholism and type I diabetes.

Another way you can boost ketone production is with a low-carb diet such as keto. The diet mimics starvation in a sense, forcing your body into ketosis due to a lack of glucose. Your body's cells pick up these ketones to converted into acetyl-CoA, a molecule that cell mitochondria oxidize for energy and even converted into long-chain fatty acids in the brain.

When ketone levels are high, there are ways to detect them in the blood, breath, and urine. Their levels can vary depending on how much your body is utilizing ketones and how much it is making.

What Are Ketones in Urine?

Having ketones detected in urine is known as ketonuria. Ketonuria is a sign that your body is using fat as its major source of energy. Acetoacetate and beta-hydroxybutyric acid are the two most commonly found in urine while acetone exits your body through breath.

There are many causes of ketones in urine such as uncontrolled diabetes, starvation, eating disorders, alcoholism, and, of course, the keto diet.

Keto dieters use urine test strips to test for ketosis. However, they're not always accurate as ketone concentrations in urine change when you become keto adapted. That's because your body has become more efficient at utilizing ketones so fewer spill over into urine.

Is Ketonuria Healthy?

Studies show that people prone to ketonuria are in better metabolic health than those who rarely have ketones in urine after fasting [2]. That's because ketones in urine are a sign that your body is efficient at burning fat, which is essential for metabolic health.

Ketones in the urine are a sign you've reached ketosis on a low-carb diet. However, their levels should begin to drop after a few weeks on the diet. If this doesn't happen, it could either mean your body is not using ketones or that its making more ketones than necessary.

However, ketones in urine can sometimes indicate a problem. When concentrations are excessively high, it can mean your body is lacking glucose or insulin. Overproduction of ketones happens in some disease states and leads to what is know as ketoacidosis. Ketoacidosis causes blood to become acidic from too many ketones. Luckily, ketoacidosis is rare in people without type I diabetes [3].

Testing for Ketones in Urine

Ketones in urine are measured with urine test strips. Most detect acetoacetate concentrations. Low concentrations are a value of under 20 mg/dl; moderate concentrations 30–40 mg/dl, and 80 mg/dl and above is considered a large concentration of ketones in urine [4].

Urine test strips usually come with a colored scale to help you compare your results. The scale usually comes in light to dark purple shades with the darkest shade indicating the highest concentration of ketones.

Another sign that there are ketones in urine is a sweet smell. Ketones produce a strong, fruity type of smell. It's also the smell many dieters notice on their breath the first time they go keto. This unpleasant smell is only temporary, so you don't need to give it too much thought.

Other Ketosis Symptoms

Besides having ketones in your urine, there are many other ways to test for ketosis. Blood ketone meters and ketone breathalyzers also test for ketones. However, they are fairly expensive. Many keto dieters also don't really benefit from testing ketones, so it's up to you to decide if these devices are worth the splurge.

A much cheaper way to test for ketone levels is looking for signs. First, the initial signs of ketosis on a keto diet can be quite uncomfortable. These are often termed the "keto flu" and include the following:

  • Keto breath – often described as fruity
  • Fatigue and headaches
  • Frequent urination
  • Muscle soreness
  • Insomnia
  • Brain fog

These symptoms are only temporary. They're the result of electrolyte imbalances, glycogen depletion, and rising ketone levels. You can learn more about the keto flu, including ways to alleviate it here.

Ketosis Signs

Once you become keto-adapted, you'll experience the more positive signs of high ketone levels. These signs include:

  • Increased energy
  • Mental alertness
  • Healthy weight loss
  • Reduced appetite

The above symptoms mean your body is utilizing ketones which are a much more efficient and healthier source of energy. Studies also show that people with certain medical conditions also notice improvement in their health and well-being on a keto diet [5].

Ketones help treat epilepsy, Alzheimer's, Parkinson's, ADHD, and many other neurological conditions. They also improve metabolism functioning and increase longevity. But all in all, ketones in urine are a good sign your body is going through positive changes which you'll feel as better overall health and increased levels of well-being.


Ketones in urine are symptom of greater ketone production. When your body is making an excess of ketones, they spill over into urine and some get released through breath. Once your body starts utilizing ketones fully, less get lost through urination.

Having ketones in urine is more often than not a good thing. It's a sign that your body is efficient at burning fat, meaning you are in good metabolic health. Ketones at healthy levels also improve brain functioning and overall health.

However, abnormally high levels can be dangerous. This often happens to people with uncontrolled type I diabetes, alcoholism, and even eating disorders. In healthy people, however, the body is perfectly capable of keeping ketone production at health levels.

To test for ketones in urine today, check out our Ketone Urine Test Strips. One packaging contains 200 test strips and you get results within seconds.


  1. Ward C. Ketone body metabolism. 2015, November 18 -
  2. Joo NS, Lee DJ, Kim KM, Kim BT, Kim CW, Kim KN, Kim SM. Ketonuria after Fasting may be Related to the Metabolic Superiority. 2010, November 24 -
  3. El Hefnawy M. Epidemiology of Diabetic Ketoacidosis in National Institute of Diabetes and Endocrinology (NIDE) by:Bassyouni, A.; El Ebrashy, I.; El Hefnawy, H. 2012, May 09 -
  4. Comstock JP, Garber AJ. Clinical Methods: The History, Physical, and Laboratory Examinations 3rd Edition Chapter 140 Ketonuria. 1990 -
  5. Gasior M, Rogawski MA, Hartman AL. Neuroprotective and disease-modifying effects of the ketogenic diet. 2006, September -

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