Key takeaways

Ketones are produced by the liver from fatty acids when there’s not enough glucose for energy, serving as an alternative fuel for the body, but can become dangerous if levels are too high, especially in people with diabetes.
In individuals without diabetes, ketone production is generally not harmful, but for those with diabetes, high levels of ketones can lead to dehydration, blood chemical imbalance, coma, or even death.
Ketone levels can be measured through urine or blood tests, with specific ranges indicating safe (negative ketones), low to moderate, high, or very high levels, and it’s critical to seek emergency medical attention if ketone levels are greater than 1.6 mmol/L.
Symptoms of high ketones include unquenchable thirst, frequent urination, dry mouth, high blood sugar, and, if untreated, can progress to more severe issues like confusion, nausea, vomiting, and diabetic ketoacidosis (DKA), which is life-threatening.

Due to the popular low-carb ketogenic diet, ketosis, or the process of burning ketones, has become a big buzzword. Previous to this fad diet, ketones were really only known to healthcare professionals and those with diabetes—and were not necessarily a good thing. So what are ketones, and can they be dangerous? Learn more in the sections that follow.

What are ketones?

“Ketones are water-soluble molecules that are produced by the liver. They are formed from fatty acids within the body when your body doesn’t produce enough insulin to convert glucose into energy,” says David Nazarian, MD, at My Concierge MD in Beverly Hills.

Simply put, ketones (or ketone bodies) are an alternative fuel that is made in your liver when there is not enough glucose (sugar) for energy. When your body doesn’t have enough sugar or glucose for energy, your body needs a new energy source. Your body will then switch to breaking down fat for energy. This process is done in the liver, where fats are turned into a chemical called ketones. The ketones, a fatty acid, are then released from the liver and go into your bloodstream and are used as fuel to drive the body’s metabolism and to support muscle function.

The body typically needs ketones when insulin levels are low. Examples of times when your body produces ketones include fasting, eating low-carb diets, or overnight when sleeping.

In uncontrolled Type 1 diabetes, ketones may be produced due to lack of insulin-producing beta cells of the pancreas or a lack of an exogenous, or outside insulin source.

Measuring ketone production can be done with urine testing. The safe amount of ketones in urine varies from person to person and depends on their underlying health conditions. While some people can have ketones in their urine and it is normal, others should be concerned if there is a ketone build-up as this could be indicative of a more serious problem.

Are ketones dangerous?

For those without diabetes, the body producing ketones is not typically an issue. However, in people with diabetes, the production of ketones can be very dangerous and harmful to the body. This is because the body can’t regulate insulin, glucagon, and other hormones in those with diabetes.

“High levels of ketones can be dangerous and can cause health issues. Dangerously high levels of ketones in our bodies usually occur in insulin-dependent diabetic type one patients who do not take their insulin,” said Dr. Nazarian, “It can lead to dehydration and can also change the chemical balance of your blood. Your blood becomes more acidic which if not corrected can lead to a coma or death.”

Here is a chart with the range of ketones:

Ranges to determine ketone body levels
Negative ketones	less than 0.6 millimoles per liter (mmol/L)
Low to moderate ketones	0.6 to 1.5 mmol/L
High ketones	1.6 to 3.0 mmol/L
Very high ketones	greater than 3.0 mmol/L

How to test ketone levels?

If your ketone levels are low-moderate, call your doctor to discuss these levels to receive further testing. When visiting the doctor they will likely perform a urine or blood test to determine ketone levels and perform a blood sugar test. For ketone levels greater than 1.6 it is important to seek emergency attention as symptoms could be life-threatening.

The level of ketones in the body can be assessed at home with an at-home urine test kit or with a blood meter. The urine kit typically comes with a cup and test strips that you dip into the urine. The most accurate way to measure ketones, and is the gold standard in healthcare, is through a blood ketone meter (a ketone meter and a glucose meter do not measure the same thing).

Symptoms of high ketones

Symptoms associated with high ketone levels typically include:

Unquenchable thirst
Frequent urination
Dry mouth (xerostomia)
High blood sugar levels (over 240)

If symptoms are left untreated they could progress to additional and more serious symptoms including:

Confusion or difficulty focusing
Fatigue
Nausea
Vomiting
Dry or flushed skin
Difficulty breathing
Breath characterized by a fruity smell
Abdominal pain

If ketone levels are still left untreated after these symptoms an even more serious complications can arise with those with Type 1 diabetes, and occasionally for people with Type 2 diabetes, called diabetic ketoacidosis (DKA). This will cause blood to become acidic. This is a serious and life-threatening issue that can lead to brain swelling, diabetic coma or death.

New diabetics are recommended to check their ketone levels twice daily when they are first diagnosed.

For those without diabetes and want to achieve ketosis for weight-loss reasons, the amount of ketones to signify being in ketosis is 0.5 mmol/L ketones or in their blood or urine.

RELATED: Ketosis vs. ketoacidosis

What to do if ketone levels are too high?

If your ketones are too high based on ketone testing, it is important to seek emergency medical treatment. You will likely have the symptoms listed above and it is possible it could lead to DKA.

This condition is treated by a medical professional within a hospital. Some common ways to treat are:

IV fluids to help the patient from becoming dehydrated due to frequent urination
Electrolyte replacement to help boost the lost electrolytes.
Insulin is typically used to help the body convert back to running on glucose instead of ketones for energy.

Ways to prevent ketones from reaching too high are to manage diabetes regularly. This can be done by:

Checking blood glucose levels regularly
Eating a healthy diet
Checking for ketones if blood sugar is above 240 mg/dl
Managing correct insulin dosages

While people without diabetes can have ketones in the urine, DKA is only an issue for those with diabetes.