A Detailed Guide On How To Test Your Ketone Levels

I have to be honest with you. I’ve been making some critical mistakes. I was assuming that I was in ketosis for months but I’m now finding out that isn’t the case. Not even close.

I’ve finally hunkered down and have been measuring my ketones the right way and the results have been pretty surprising. I was eating too much protein, and too little fat. I was eating too frequently. I was eating too few calories. I never would have known this without testing. Time for you to learn from the mistakes I made and test the right way.

Ketosis can be a powerful nutrition approach to use switch your metabolism to prioritize for fat loss, mental output, physical performance, and much more. The main problem? Many people just assume that if they are “low carb” they are in ketosis, but think again. How do you know if you’re actually in ketosis? As I love to say, “test, don’t guess” when it comes to your health. (Still trying to get “track, don’t slack” to catch on…)

I’ll outline in this article the three ways to test your ketone levels and which you should be doing when.

How to test your ketone levels


There are three testing methods because there are three forms of ketones in your body: acetate, acetoacetate, and beta-hydroxybutryate. Each of these ketone bodies do slightly different things and are in different forms, so they can be tested individually with different methods.

The three different area these ketones exist in your body are your breath, urine or blood. The good news is that all of these ketone level measurements can be done at home, by yourself. You don’t need to go to a lab or use any fancy high-tech gadgetry.

Tracking consistently, at least when you’re getting used to a ketogenic diet, is important so you know how much you react to different variables like exercise, type and amount of food, and amounts of exogenous ketone supplements among other variables.

Also, the ideal level of ketones can vary per individual and their specific goals. For example, I feel best over 2.0 mmol when measured through the blood, but I know some people who are best at over 1.5 mmol. Knowing the amount where you are reaping the benefits you want (and consistently checking if you’re hitting that amount) is the fastest way to see results.

How to test your ketone levels

KETONE TESTING OPTION ONE: Testing ketosis with urine strips (acetoacetate)

One of the three ketone bodies, acetoacetate, can be measured directly through your urine.

The way metabolic substrates (things your body uses for metabolism), like ketones, get into your urine is if they are “spilling over” in excessive amounts. If there is an excess of a certain metabolic substrate, or if you are not using a substrate (so, an excess), it can be dumped into your kidneys to be excreted in your urine. This is actually a good thing that excess ketones can be excreted through your urine.

When carbohydrates increase in your blood to an excessive level, insulin is secreted, and then they convert to fat. This process also includes a hike in inflammation. When ketone body levels are at an excessive level, they are just excreted through your urine instead of having to be stored as fat. Good thing.

As your body begins producing and using ketones they will not all be used up. Your body has to go through a stage of “keto adaptation,” simply meaning it needs to get used to using ketones as energy. Until then it won’t be efficient at doing so and will excrete some ketones through your urine. The way to measure these excess amounts of ketones is through a simple urine strip. The strip changes colors relative to the amount of ketones in your urine and bam, you can tell roughly what level of ketones are in excess.

This is unfortunately not always a reliable test. Once your body is in the “keto-adapted” state, it will be very efficient and using the acetoacetate that it produces from your body fat and dietary fat and you will have a lower level of ketones that are reading on the strip. This is misleading. You are actually in a deeper state of ketosis but the strip says you have less ketones. There are just less spilling over into your urine.

Other factors that can modify your urine levels are electrolyte and hydration levels, which affect the solution of acetoacetate in the urine and can give variable readings.

Another problem is that the strip turns shades of a color to tell you how many ketones are in your urine. There is very little consistency here so it can be difficult to say if something affects your levels because random shades of colors aren’t a reliable outcome measurement.

Key advantages of testing ketone levels using a urine strip is that is very easy and very cheap to do. You can purchase a pack of 100 strips for about $8.

How to use a urine strip to read your ketone levels

Taking the “test” is pretty easy. All you do is pee on the stick, tap any excess urine off, then wait a certain amount of time (usually 45 seconds) to see if there are detectable levels in your urine. Refer to the package for amount of ketone bodies in the urine after a certain time from peeing on the stick. Usually the darker purple color on the strip, the more ketone bodies.

Urine strips can be a great method if you are just starting to get into ketosis and want to see the transition, but probably aren’t a good long term or consistent measure once you’ve been in ketosis.

Pros of testing ketosis levels with urine strips: Quick and easy. Strips are affordable.
Cons of testing ketosis levels with urine strips: Can get messy. Only accurate some of the time. Not a precise measurement.

How to test your ketone levels

KETONE TESTING OPTION TWO: Testing ketosis with your breath (acetone)

Acetone or acetate is the second ketone body we’ll be looking at measuring and is produced by gas exchange in your lungs. Since that is the case, you breathe out a detectable level of ketones. While not directly responsible for metabolism and more of an indirect measure, acetate has been found in recent findings to correlate very closely to levels of BHB in the blood. The blood is what exchanges gases in the lungs, FYI.

Acetate/acetone can be measured directly through the breath with use of a Ketonix device by breath acetone, or “BrAce.” BrAce is measured in parts per million, or ppm. Measurements of BrAce ppm can be done from 1 ppm to over 1250 ppm. There are a few different Ketonix devices that are preprogrammed to show different colors of lights blinking at different frequencies depending what levels of BrAce ppm are in your blood and have companion apps that run on your computer.

One of the key advantages of a Ketonix meter is that it is reusable and a one time purchase. Once you buy the breath meter, you can test as many times as you want, unlike urine or blood strips, which are one time use. At least I hope that’s how you’re using them.

A huge downside I’ve noticed is the inconsistency with breath meters. I can be at 2.5 mmol blood levels (see below) and will be trace acetone levels. This makes me see the breath meter as not nearly as reliable as blood meters. Or I have a bad unit. 

How to use a Ketonix breath meter to read your ketone levels

After you get the Ketonix meter, you just plug it into a USB port or into an included battery pack. Wait until the unit “warms up,” which frustratingly can take awhile. Blow into the Ketonix unit until it starts flashing that it is reading your breath acetone levels. Either use included software for your computer or the color (green color = least acetone, red color = most acetone) and number of times the color is flashing (less color flashing = less acetone per color level, more color flashing = more acetone per color). Note the color and number of flashing to be able to measure relative levels. Compare to other times to create a reproducible standard. This still isn’t as consistent as a blood reader.

Ketone breath meters are too early to the game to be used consistently. They appear to be more of a novelty for the time being. If you use them, correlate with blood meter for the first dozen or so uses.

Pros of testing ketosis levels with a breath meter: Reusable device. Doesn’t use bodily fluids.
Cons of testing ketosis levels with a breath meter: Indirect measurement. Inaccurate measurement. Takes a much longer than urine or blood tests to get a reading. Inconsistent reading.

How to test your ketone levels

KETONE TESTING OPTION THREE: Testing levels of ketosis with blood meter (beta-hydroxybutyrate)

The main ketone body that you use (or can take as a ketone supplement) is beta-hydroxybutyrate, or BHB. BHB enters the cell and is converted to acetoacetone, which can then be ultimately converted to acetyl COA and enter the Kreb’s cycle. Unnecessary biochemistry aside, the point is that BHB is mostly outside of the cell. Where is it then? In the blood, so can be circulated and carried to your cells for use.

That being said, testing levels of ketones by looking at amounts of beta-hydroxybutyrate may be accomplished by sampling the blood. This can be done easily at home the same way individuals with diabetes check their blood glucose. Prick your finger, squeeze a drop of blood out of your finger, tap it on a little strip and have the machine tell you the level of BHB in your blood.

The good news, unlike the urine test, is that your blood is a very tightly regulated system and doesn’t get diluted or change with different factors of hydration. That means this is the most direct way to measure the level of ketosis.

The downside to the blood ketone meters is that some people may have a strong aversion to pricking themselves with a tiny needle and using their own blood for a measurement. Not to mention, the testing strips are considerably expensive, usually $5-$10 per strip. This can add up if you are testing a couple times a day to track changes in ketone levels.

How to use a beta-hydroxybutyrate blood meter to read your ketone levels

One of the most reliable and consistent meters for measuring BHB levels in your blood is the Precision Xtra meter. Before you draw blood, it is recommended to use an alcohol swab to cleanse the area you are testing (your finger, hopefully) to minimize the risk of infection. Use a fresh lancet every time (the needle that pokes you) and use the included spring loaded mechanism to draw a drop of blood, for the same reason. Place blood onto strip and wait 10 seconds for a reading.

The blood level of BHB is measured in millimolar concentration, or “mmol”. Studies have shown most optimal ranges of BHB levels for benefits of ketosis are between 1.5-3.0 mmol, however this may vary per person.

Blood testing is the only REAL way to track your ketone levels! It can be expensive, but is definitive and allows you to conclusively see responses of ketone levels to different variables.

Pros of testing ketosis levels in the blood: Extremely accurate and precise measurement. Most reliable and effective measurement of ketone levels.
Cons of testing ketosis levels in the blood: Expensive strips. Some may not like drawing blood.

Using symptoms to guess your ketone levels

If you don’t have any equipment, there are a few other signs and symptoms you can use to guess that you are in ketosis. These are not accurate enough to know the level, but can be a good gauge if you don’t have access to equipment or tools to have a definitive test. If you’ve definitively tested before, you can use this as an approximation that you’re “back in” ketosis as you’ll have a base frame of reference. 

Mental Clarity: Your brain constantly uses a significant amount of energy. When you are eating carbs, there are energy swings, therefore mental performance swings. When you are in a state of ketosis, your brain will rapidly be using ketones for fuel by using either ketone supplements or your fat stores, which are always there. There is a marked mental state in ketosis that different, and when you’re in it, you know.

Hunger Control: When your body is used to utilizing ketones, you will begin using fat to break down into ketones to use for energy. Because your body has such a constant supply of energy, it doesn’t crave food the way it would if your energy would be dependent on carbohydrate stores. If you have sharp drops in hunger pangs throughout the day, that could be a good sign of being back into ketosis. Realized you didn’t eat for last 14 hours, still have boundless enery and not hungry? Probably in ketosis. 

Sustained Energy: Approximately 90-120 minutes after you eat carbohydrates, your body doesn’t have readily available energy produced from the mitochondria in your cells, so you start “crashing” or lowering your energy. When you are in ketosis, your body can run off your body fat, which is an essentially limitless source of fuel. This prevents any type of crash in energy.

Increased Thirst, Dry Tissues: When you’re adapting to a ketosis based diet, your body will be using up excess glycogen and will be increasing the amount of urination. If you’re not adding in some salt or electrolytes you will probably be pretty thirsty with the lower levels of hydration. This will also lead to drier tissues in the short term. However, if you have chronically dry tissues on a ketogenic diet, that’s because you’re not eating enough and trashing your thyroid, not because ketones are bad. 

NOT Breath, but Mouthfeel: For ketones, you may read that if your breath is fruity smelling, this is a good indication that you are in ketosis. This is not accurate as this is a closer reflection of ketoacidosis, which is NOT to be confused with nutritional ketosis. Acetone levels in the breath under nutritional ketosis should not be high enough to cause a detectable scent. However, when you wake up in the morning, a lot of times you’ll have a distinctive mouthfeel when in ketosis that is recognizable. There’s almost a film-like feeling. You’ll know. 

How have you tested ketone levels before? Questions or comments? Leave the feedback below!