Ketosis is a metabolic state where the liver breaks down fat to produce ketones. Ketones, on a ketogenic diet, are the primary fuel source for the body. If you’re new to the ketogenic diet and you still have questions, consider reading our Comprehensive Beginner’s Guide to Keto >
There are three main ways to measure the ketones in your body, all of which have their advantages and disadvantages. The most common ways to measure are:
- Blood Ketone Meter. Very accurate but the strips are extremely expensive.
- Breath Ketone Meters. More accurate than the urine strips, but can sometimes vary in accuracy. Cheaper than blood strips in the long-run.
- Urine Stricks. This will answer the question “Am I in ketosis?” but will not provide an accurate measure of blood ketones.
Scroll down to read a more in-depth analysis of each, and what we recommend for you.
Measuring Ketones with Urine Sticks
Urine sticks will always be the cheapest and easiest way to measure ketosis. For beginners, this should cover everything you need – there is no point in getting more complex blood strips so early on when you are still trying to understand the nuances of a ketogenic diet.
Ultimately, keto sticks are very easy to use – you hold the sticks in your urine stream for a few seconds, and within 10-15 seconds you should notice a color change in the strip (if you are in ketosis). The color of the stick typically is measured in red: light pink being low in ketone production and dark purple being high in ketone production.
While keto sticks can be ideal for a general answer to the question “Am I in ketosis?”, they aren’t precise with their accuracy.
They measure the acetoacetate in your urine, which is an unused ketone by the body. As you get deeper into ketosis and your body adapts, your body will also become more optimized in ketone production.
You should notice a dark purple color when you’re newer to the ketogenic diet. If you’ve been on keto for many months, you’ll probably see a much lighter color. Many people assume this is a bad thing, but it’s usually not. Your body has just become more efficient at creating the ketones that fuel your body. If you’ve been following a ketogenic diet for a long time, it can be common for the sticks to give a false negative result.
The biggest advantage to measuring ketosis with urine sticks is that they are incredibly cheap and typically very easy to find. You can order them from Amazon, but they are usually available in pharmacies like Walgreens.
The biggest disadvantage to these is their accuracy. Besides being inaccurate if you’ve been in ketosis for a long time, the sticks can also give varying results based on your hydration. If you’re properly hydrated, many times the sticks will read a much lighter color than if you were dehydrated.
Measuring Ketones with Breath Meters
Breath ketone meters are becoming more and more popular because of their simplicity. You connect it to your computer via USB and blow into it. From there, it measures the acetate in your breath – giving a good indication of your ketone levels.
They range from $150-200, so they are a pretty expensive upfront cost. We recommend that if you’re new to ketosis, you wait to buy one until you’re at a more advanced level. While breath meters are expensive upfront, it is much cheaper than the regular purchases of blood ketone strips. In the long-run, the most economical value for the results would be a breath analyzer – since you can reuse it as many times as you want.
Research shows that there is a pretty good correlation between acetate in the breath and the level of blood ketone meters, but can vary as you get deeper into ketosis. While they are much more accurate than the urine sticks, they can vary widely against the results of a blood ketone meter. This can sometimes lead to incorrect results, which may be misleading at times.
We recommend that if you’re on a budget, but you still want to have mostly accurate ketone readings, try Ketonix. If you can afford to purchase the blood strips and are adamant about the accuracy of each result, try a blood meter.
Note: Ketonix on Amazon is from a third-party seller that is currently gouging prices. Try to order directly from their website if you want to use a breath ketone meter.
Measuring Ketones with Blood Meters
Blood ketone meters are the more accurate way to measure your level of ketosis. They show an exact and real-time measurement of the ketones in your blood, which is considered the “gold standard.” The biggest drawbacks of the blood strips are that they can get expensive quickly. They cost about $1 per strip, and most insurance providers don’t cover them.
Some slight drawbacks of blood ketone meters are their accuracy per device and their failed readings. Blood ketone readings will vary (though not greatly) between device and strips, even if they’re from the same brand. They can also occasionally fail readings, which means a wasted strip.
Remember as well that you do have to prick your fingers to draw a sample of blood for each reading. If you’re squeamish or don’t like to take blood, this may not be the best option.
You can frequently find deals online for a free meter since they are cheap. The meter companies usually use a proprietary strip that only works on their machine – so they are more interested in you purchasing strips. If you’re not a deal hunter and want the most accurate way to measure ketone production, consider ordering the Precision Xtra (you will need extra strips).
Optimal Ketosis and Ketone Readings
Ketosis has many varying degrees, which indicate the number of ketones you are producing in your blood. As a rule of thumb, the higher the level of ketone production – the better the weight loss will be.
Since the most accurate way to measure ketones are through blood meters, we’ll be using them as our primary example. Typically, if you range below 0.5 mllimole ketones per liter of blood, you are not considered to be in ketosis.
A light reading (see below) can sometimes show that you’re starting to get on the right track, but you need to hone in and adjust what you are eating. You may be seeing the effects of a ketogenic diet, but you may be able to optimize your ketone production.
Here’s a quick guide on the ranges; optimal weight loss will be in the “deep ketosis” range:
- Light Ketosis: 0.5 mmol/L – 0.8 mmol/L
- Medium Ketosis: 0.9 mmol/L – 1.4 mmol/L
- Deep Ketosis (best for weight loss): 1.5 mmol/L – 3.0 mmol/L
If you’re within deep ketosis ranges, you don’t have to strive for even higher readings. If you’re falling over the 3.0 mark, you won’t have any better or worse results than if you had a reading in the 2.5 range. Frequent high readings can sometimes show a lack of calories in your diet (ketosis also happens during starvation when the body needs to break down stored energy). Make sure to use our keto calculator to find your macros.
As a side note, it is important to talk about higher levels of ketones. Values over 6.0 mmol/L can usually show the beginning of a dangerous state known as ketoacidosis. While it’s almost impossible to get to these ranges on a standard ketogenic diet alone, type 1 diabetics can sometimes notice this when their insulin levels are extremely low. Very high levels of ketones require medical attention and should be treated immediately.