People who follow a ketogenic often will utilize different test/specimens to measure ketone values in the body.

These methods typically include urinalysis, blood sampling, and breathing tests. You can do these tests through a clinic/lab, but it is much more convenient to do them at home with over-the-counter measuring devices.

Ketone levels in the body range from zero all the way up to 4 or more millimoles per liter (mmol/L). For reference, see the ranges below to determine your ketone body levels:

Read on for in-depth descriptions of the different methods for testing ketone body levels.

Urine Testing for Ketones

Method: Urinalysis for ketone body can be done by utilizing specific OTC thin plastic strips with a small reagent area on them. These are typically sold under the brand name Ketostix at most pharmacies.

You simply urinate a small amount onto the strip and check for any color changes that occur with the strip’s reagent. Different colors designate different levels of ketone bodies present in your urine.

Pros: Urinalysis is the simplest and most affordable means of testing for ketone bodies. Pretty much any pharmacy will have Ketostix available.

Cons: Unfortunately, urine testing for ketone bodies is the least reliable method in terms of accuracy. The longer you follow a ketogenic diet, the more adapted your body will be at utilizing ketones.

In turn, urinalysis can have misleading results by coming up negative. However, for people who are new to the ketogenic diet, urine testing will be useful in the short-term to measure ketones.

Blood Testing for Ketones

Method: Much like a diabetic uses blood glucose measuring lancets, the same method can be employed for measuring ketone bodies in the blood. Simply prick your finger and put a drop of blood on the ketone measuring strip.

Pros: This is the most accurate means of testing for ketone bodies, specifically BHB, and it’s rather simple too.

Cons: Ketone strips for blood testing are not very cost-friendly, sometimes upwards of $10 per strip. You might be able to shop around online and find them cheaper, but don’t expect to find anything less expensive than Ketostix.

Breath Testing for Ketones

Method: The Ketonix breath meter is the best tool for breath testing; it measures the amount of acetone in your breath.

Pros: The upfront cost is a little high, but you can a breath meter for a long time, so it pays off quickly.

Cons: Checking for acetone is not necessarily a reliable means of assessing acetoacetate or BHB levels in the body. You should use this testing method in conjunction with another method.

Ketone Level Warning Signs and Myths

Excessively high levels of ketones in the body can be detrimental, particularly when reaching the point of ketoacidosis.

Ketoacidosis is when your blood becomes acidic from extremely high ketone production. This condition tends to be most common in diabetics, so exercise caution if you’re diabetic and following a ketogenic diet.

Be sure to note that ketoacidosis is not the same as nutritional ketosis, which is healthy and safe.

The majority of people won’t have to worry about ketone production in the body while on a ketogenic diet. The body does a good job of either using or eliminating excessive ketones.

Myth: Purple Ketostix always means I’m in ketosis

Ketostix are quite unreliable for measuring actual nutritional ketosis as they measure levels of acetoacetate instead of beta-hydroxybutyrate (BHB).

Thus, Ketostix can result in false positives and “trick” people into thinking they’re in ketosis when they’re not.

Moreover, the body may excrete very little acetoacetate in the urine when you’re actually in a keto-adapted state. Remember, BHB is the dominant ketone body you produce.

This would lead to Ketostix, suggesting you’re not in a state of ketosis despite having high blood BHB levels.

For a more accurate measurement of nutritional ketosis/blood BHB levels, you need to purchase a blood ketone monitor either online or from a local pharmacy.

These devices work very similarly to blood glucose monitors and require a simple finger prick to determine how many ketones are in the blood.

Myth: The darker my Ketostix, the better

If anything, having very dark Ketostix would be a sign of concern. A dark color means you’re reaching a critical state of acetoacetate production in the body, which is a condition called ketoacidosis. Ketostix are relatively useless for measuring nutritional ketosis.

In fact, Ketostix are for helping diabetics avoid ketoacidosis and not for laypeople to measure BHB levels in the blood.

To get a more accurate measurement of nutritional ketosis and blood BHB levels, you need to purchase a blood ketone monitor either online or from a local pharmacy.

These devices work very similarly to blood glucose monitors and require a simple finger prick to determine how many ketones are in the blood.

Myth: Ultra-high ketone levels are best for rapid fat loss

Ketone bodies are not inherently fat-burning molecules in the body; rather, they are a source of energy. This would be analogous to saying that having a large amount of cholesterol in the bloodstream is indicative of fat burning.

However, there is some preliminary research that suggests rats eat less when they supplement with exogenous ketones, which has positive ramifications on weight loss. But the main thing to note is that more is not always better.

Tissues can directly use ketones or convert them to acetyl-CoA; acetyl-CoA can then be fed into metabolic pathways in the body and used for energy production.

With that being said, ketone bodies are much less likely to be stored as fat than protein and carbohydrates. In that sense, ketogenic diets are a great way to promote weight loss and minimize excess fat gain when trying to build muscle.

If you consume an exorbitant amount of ketones from supplementation, the body (specifically the kidneys) will rapidly work to filter ketones out through urine rather than converting them to fat tissue.

Again, this is not to say that you can’t gain fat if you consume an abundance of exogenous ketones. Rather, your body is less prone to convert excess ketones to fat than other macronutrients.


Q: Should I buy KetoStix to track my ketone body levels?

A: KetoStix are not a necessity when beginning a ketogenic diet. Being in a state of clinical ketosis is not a requisite for benefiting from this type of diet. Moreover, nutritional ketosis is often intermittent; if you’re on a TKD or CKD, KetoStix may give you errant results due to short-term carbohydrate intake.

Q: What’s the best way to tell if my body is producing enough ketones?

A: The three ketone bodies humans produce have a distinctive smell, which you can detect in your breath. Your urine will also smell of them (if the other urine smells don’t overwhelm them).

The smell is difficult to describe; some people note that it smells like overly ripe apples. Once you smell ketone bodies, you’ll realize it’s a very distinctive, unique smell that leaves a metallic taste in your mouth.