3 Ways to Measure Ketones – #2 is Our Favorite!

Fueled by ketones
(Image from The Keto Diet for Women)

You’re starting a ketogenic diet, and you keep hearing people talk about how the weight is just going to fall off, and how amazing you’re going to feel once you’re in ketosis.

Ahhh, ketosis. That magical state when you’re fueled by fat and feeling fantastic. Before we go too far, let’s talk about exactly what ketosis is, how you get there, and what it means for your body.

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Ketosis… What does that even mean?

According to WebMD, “Ketosis is a normal metabolic process, something your body does to keep working. When it doesn’t have enough carbohydrates from food for your cells to burn for energy, it burns fat instead. As part of this process, it makes ketones.”

Glucose vs. ketones

Although that’s a fairly simple definition to understand, let’s simplify it a little more.

Under normal circumstances, your body burns glucose (carbohydrates) for energy. Once it has used up all of the glucose that it needs for energy, the rest is stored on your body as fat.

This is the underlying idea behind low carb diets in general. If you keep the number of carbs fairly low, then you won’t have excess glucose to store as fat on your body, keeping you from gaining weight.

On a ketogenic diet, we switch up our metabolic process. We start by cutting carbs significantly (most experts recommend 20 net carbs or fewer per day). This triggers a reaction in your body.

Your body is accustomed to using that glucose for energy, but when it doesn’t get it, it goes into sort of a panic mode. It starts looking for other sources of fuel, and turns to fat instead.

If you’re doing a ketogenic diet, then there isn’t any excess glucose to be stored as fat. If you manage your macros well enough, you won’t have any excess fat, either. The fat you’re taking in will be burned for energy.

Ketogenic diet flowchart
(Image from Bodybuilding.com)

So what in the world are ketones, then? The process of ketosis is fairly easy to understand, but it’s important to know what ketones are, and how to test your levels – something you may want to do fairly often.

Ketones are simply chemicals made in your liver. They are a type of acid that is made when the body breaks down fat for fuel. Your liver sends the ketones into your bloodstream so that your muscles and other tissues can use them for fuel.

People who are in ketosis – the state of your body being fueled by fat – often report pretty amazing effects. You’ll hear about people having more energy, more mental clarity, weight loss, management of PCOS symptoms, better athletic performance, lowered inflammation, and more stable moods.

Fueled by ketones
(Image from The Keto Diet for Women)

However, not everyone feels these effects so plainly. For some, until you start losing weight, it’s not really clear whether or not you’re in ketosis. Even after you’ve started to lose weight, you might hit a plateau, and it’s nice to be able to confirm that you’re actually being fueled by fat.

So how do you do this? There are three ways that are fairly well known, although some are more trustworthy than others. Let’s explore the three ways to test your ketones (aside from visiting a medical laboratory!).

How to test ketones
(Image from Perfect Keto)

1. Urine Strips

Probably the most common way to test ketone levels, ketone strips can be purchased in most pharmacies and drug stores. (If you’re having trouble finding them, check with the pharmacist; sometimes they’re stored behind the pharmacy counter.)

Keto sticks
(Image from Diabetes Duo)

So here’s the deal with ketone strips (a popular brand is called Ketostix – easy to remember!). First, don’t mistake them for blood test strips. That’s another way to test your level of ketones, but we’ll get into that shortly. Just make sure you don’t run out and buy the blood testing strips, thinking you’re getting urine strips!

Testing your urine for ketones is very simple. You run the strip under your urine stream (I’ve also heard of people urinating in a cup, then dipping the strip into the cup – whatever makes you happy!) for a few seconds (the specific brand of strips that you buy will give you directions on exactly how long the strip has to be exposed to the urine).

After the urine has processed on the strip, you simply check the color of the strip. It changes color corresponding to a chart that shows your ketone level. Most of the bottles that the strips come in will have a diagram that runs from negative ketones to “large.”

If you’re interested in the science here, ketone strips actually measure the excess ketones in your urine. This means that if you have negative ketones in your urine, your body is not fat adapted, and is not effectively producing ketones. On the other hand, if you’re on the opposite end of the chart, with a large amount of excess ketones, you’re likely in ketosis.

(Image from Diet Keto)

Something important to note, however, is that testing your ketone levels with urine strips isn’t always accurate. Our bodies produce three different types of ketones: acetate, acetoacetate, and beta-hydroxybutyrate. Urine strips only measure acetoacetate, which means that your results aren’t always exactly right. If you’ve been in ketosis for a while, your body produces different amounts of the various types of ketones, so what you’re seeing on the strips isn’t always the full picture.

So if the urine strips aren’t always accurate, why would you use them? Well, sometimes it takes days for someone to get into ketosis, but for other people, it could take a week or more. If you want confirmation that your body is producing ketones, the strips are usually pretty reliable for that. If you’ve had a big cheat day and you want to see just how likely it is that you’ve gone back to burning carbs (kicked yourself out of ketosis, essentially), the urine strips will definitely show if you’re not in ketosis anymore.

When should you NOT use urine strips? When you want to know specifically what your blood ketone levels are. When you want to get into the nitty-gritty and get exact numbers, urine strips aren’t the way to go. We’ll discuss more viable ways to test in those scenarios in numbers 2 and 3 below. But first, let’s do a recap of using urine strips.


  • Urine strips are significantly cheaper than other methods of measuring ketones.
  • They are pretty reliable when you’re first starting keto, or if you’re concerned that you’re out of ketosis.
  • They are easy to use. You might not want to pee on a stick, but it’s not that difficult and it’s painless.


  • Urine strips are the least accurate way to measure your ketones, if you want specific numbers.
  • You have to pee on a stick. Gross.
  • You probably won’t use them that often, and they do expire after a while, so you’ll probably end up buying new ones before you run out of the old ones.

2. Blood Ketone Monitors

Blood ketone monitors are a great way to check your ketone levels, and are perhaps the most accurate method. You’re probably familiar with this type of testing, as diabetics use very similar monitors to check their blood glucose levels. There’s a lot to know before starting to test with a blood ketone monitor, so let’s look at all the factors to consider.

Ketone meter
(Image from Diabetes.co.uk)

First, know going into the situation that it’s not going to be cheap. If you really need to test for ketones and you can’t afford to spend much money, you’ll likely have to go back to method number 1 – urine strips. When you test with blood ketone monitors, there are a lot of parts that have to be purchased.

You’ll need a blood ketone monitor. There are several on the market, but be very careful when purchasing one: even when searching specifically for “blood ketone monitor” you’ll get lots of results for blood glucose monitors. While some of them measure glucose and ketones, not all of them do.

A few common brands are Precision XtraNova Max, and Multisure. Prices definitely vary when you’re searching for monitors so be sure to shop around and find one that fits your needs.

In addition to purchasing a monitor, you also have to buy ketone test strips. You cannot use ketone strips and glucose strips interchangeably, although some monitors test for both. The ketone test strips are often where the real cost comes in. (I recommend this Precision Xtra pack.) Again, just like with the monitor, make sure that you don’t accidentally buy glucose strips. They are NOT interchangeable and you’ll have wasted your money.

Finally, you’ll need lancets that will be used to prick your finger. Sometimes these come in a kit with the monitor, but not always, so make sure you check what you’re getting before you buy! If this seems like a lot to keep up with and a lot to remember, consider buying a ketone testing kit, like this one from Precision Xtra. With a kit, you usually get everything you need – monitor, test strips, and lancets – all in one. If you’re intimidated by the idea of purchasing everything and making sure it all works together, just go with a kit.

Ketone testing kit

So now you’ve got everything you need to test your blood ketones. Let’s talk about how you actually do that!

As I mentioned before, you may be familiar with the process if you’re diabetic or have seen someone check their blood glucose levels. It’s basically the same procedure.

  1. The first step is to load the lancet pen with a lancet. This is usually pretty straightforward; there is often a round cap on the needle end. Twist this cap off, and insert the other end into the lancet.
  2. Make sure your hands are clean. Wash them or use an alcohol wipe to avoid any risk of contamination.
  3. Insert a test strip into the monitor. (For most monitors, this will turn the monitor itself on.
  4. Place the lancet pen on the side of your fingertip (you get better blood flow there, and it’s less painful!) and press the button.
  5. Squeeze out a drop of blood and apply it directly to the end of the test strip. You’ll see the strip pull the blood in and the meter will register.
  6. Wait a few seconds for your results, and record them if you’re tracking your results.
Blood testing ketones
(Image from Ketogenic Diet Resource)

Pricking your finger may not be your idea of fun, but this method of testing your ketone levels is definitely the most accurate. If you’re just checking to see if you’re in ketosis yet, or want to see if you’ve been kicked out of ketosis, blood ketone monitors probably aren’t necessary for you.

However, some people find that they want to check their blood ketone levels to see how their bodies are responding to certain foods. For example, some of us are totally okay with artificial sweeteners – we guzzle diet drinks, snack on low carb protein bars, and fill our junk drawers with those Atkins snacks – no problem!

But others find that the artificial sweeteners in these products kick them straight out of ketosis. It’s an interesting experiment to test your ketone levels before and then after eating certain foods. As we all know, every single body responds differently to different triggers, so this could be a way to determine exactly what your body will – and won’t – put up with.


  • This method of ketone testing is usually considered the most reliable method.
  • You get accurate results in seconds.


  • This method will cost you quite a bit more than the urine strips, and you’ll have to continue buying more test strips as you use them.

3. Breath Testing

While this is the method that I’m the least familiar with, it’s definitely worth talking about! This method actually tests the level of acetone in your breath. This is definitely a preferred method for some people because it’s less invasive than testing your blood (no needles!) and it’s more accurate than testing your urine. (It’s worth pointing out that testing your breath acetone levels isn’t always completely accurate, but is more so than urine testing.)

Keto breath testing
(Image from Katrin Mager)

If you’ve ever blown into a Breathalyzer, then you pretty much know how the Ketonix Breath Analyzer works. It’s a relatively simple product with a relatively simple application. The problem with the Ketonix Breathalyzer is that it is quite costly. There are several versions that you can choose from – the cheapest version is a small USB version without a battery. If you want the latest version, try the Ketonix Bluetooth with Battery. Of course, the benefit here is that it’s a one-time cost, as opposed to the blood ketone monitors, where you’ll have to replace your test strips fairly often.

The best part about using the breath analyzer is that all you have to do is breathe, quite literally. No pricking your fingers, no peeing on a stick. You just breathe into the little tube and it gives you your results. Obviously, as it’s a USB device, you have to plug it into your computer to download the program, and create a profile. Once you’re all set up, you can get started with testing.

The procedure itself is very simple. The following steps are written directly on the device:

  1. Connect to USB port
  2. Wait until LED turns blue
  3. Blow gently into mouthpiece for 10-20 seconds
  4. Read color after 30 seconds

Each color designates a different level of ketones in your breath. The higher ranges, which cover 400 to greater than 930 mmol/L, denote nutritional ketosis. It’s as simple as that!


  • This test is easy to take – no pricking your fingers, and no peeing on sticks.
  • While the test isn’t always 100% accurate, it’s more accurate than the ketone strips.


  • The one time fee is pretty high.
  • This isn’t the most accurate type of test that you can take.

Can you just sum it all up for me?

Of course I can! Basically, there are two factors to consider if you want to test your ketone levels: the cost that you’re willing to incur, and the accuracy level that you’re expecting.

Low Cost, Low Accuracy: Urine strips
Average Recurring Cost, High Accuracy: Blood Ketone Monitor
High Cost, Average Accuracy: Ketone Breath Analyzer

Once you’ve decided which combination of cost and accuracy is best for you, you’re on your way to testing your blood ketones and maintaining a state of nutritional ketosis. Good luck!

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