Ketone breath meters

What are ketone breath meters

Ketone Breath Meters-what are they, how accurate are they and how to use them if your following a keto diet

how to use a ketone breath meter

Ketone breath meters are a great way to monitor if your in ketosis and if your keto diet is working. They are much simpler to use than ketone blood meters, in which you need to obtain a blood sample using a finger prick blood test, but are they as accurate?

Ketone breath test accuracy

The simple answer is no a ketone breath meter is not as accurate as a a blood ketone meter, but for most people, and particularly those who are not keen on doing repeated blood samples, which includes me, they are accurate enoug, if used correctly and can be a very motivating tool to show you when you are in ketosis and to what degree and this can help you stick to you keto diet.

I have also found that if i use perfume, and then test my breath ketone levels, the ketone breath meter may give a much higher reading than I was expecting, as it is picking up the alcohol in the perfume which I have inhaled.

I have been using a ketone breath meter for over 6 months now and have found it to give a good indication of my level of ketosis. 

How does a ketone breath meter work

All ketone breath meters work by measuring the concentration of acetone in a breath sample, in parts per million. This is different to a blood ketone meter which actually measures ketone levels in your blood.

The ketone breath meter is very sensitive and can not distinguish between acetone and alcohol on your breath, so it is will not give you an accurate result if there is any alcohol on your breath for example, if you have been drinking heavily the night before,  or have recently had a drink of alcohol, or used a mouthwash containing any alcohol. Just something to be aware of.

Best time of day to check your ketone levels with a ketone breath meter

I have found the best time of day to check my breath ketone levels with the ketone breathalyser is first thing in the morning as soon as I get out of bed. I practice intermittent fasting as well as following a keto diet, and will usually get the highest level first thing in the morning. 

How to use the Valuemed ketone breath meter

How to use a ketone breath meter

  • Apply a mouthpiece to the ketone meter ( if you are just using the ketone machine for personal ketone testing then this can be left on and cleaned as necessary, if you are testing multiple individuals then you will need a new mouthpieces for each person )
  • Switch the ketone meter on (make sure that it has batteries in)
  • The ketone breath meter will count down from 20
  • When it gets to 0 you start to blow for 10 seconds to calibrate the machine ( this can be harder than it sounds)
  • The breath ketone meter will make a sound when you have blown for the required time and you can then stop blowing
  • Then do a second ketone breath test in exactly the same way and use that reading as your ketone level

What sort of readings should I expect with the Valuemed ketone breath meter

ketone breath meter readings

These are the reading that I have obtained from my ketone breath meter over the last 6-8 months of using it:

  • Not in ketosis reading is zero
  • Mild ketosis reading around 0.30
  • Moderate ketosis reading around 1.70
  • Full ketosis reading around 2.90
  • Alcohol on my breath reading much higher
  • If you get a red light it means the breath sample was inadequate so you need to repeat the test from the start again
  • A yellow/amber light means the battery needs changing

How long will it take me to get into ketosis

When i first started the keto diet that I am following, I found it took me several days before i was getting any readings with the ketone breathalyser which was initially disappointing.

I was expecting to get high readings straight away, but I now know from reading around the subject that this is fairly common experience if you have never done a keto diet before. I was a big carbohydrate consumer and had been eating high carb low fat for many years, and so my body was used to burning carbohydrates as its main source of fuel. I rarely went hungry and was always snacking on carb rich foods.

Since following a low carb higher fat diet for the last 8 months I have found that my body is much faster at getting back into ketosis. If I have a day when I consume more carbohydrate, I can usually get back into full ketosis the next day if get straight back on to my keto diet.

Another reason that it can take several days to get into full ketosis when you first start, is that you will need to use up your glycogen stores in your liver before your body starts to burn fat. If you have been following a high carbohydrate diet your glycogen stores will usually be larger than if you are following a low carbohydrate diet.

Where can I buy a ketone breath meter

They are widely available to buy online. If you want to buy the one I have been using then it is available in the ketone meter section of this website.

Buy ketone breath meter for just £24.99 with free UK delivery

Useful books to read for inspiration when you are going low carb

  • Dr Michael Mosely has written several books on the subject which I have found very helpful including the FAST diet and the Fast 800 diet. I have also read his original book the 5:2 diet which is helpful if you wish to also use intermittent fasting, which is great for getting you into ketosis quickly. It is also worth watching his videos on  the same subjects on You Tube and his original Horizon programme Eat, Fast and Live Longer about diabetes and pre-diabetes that started him on his low carb journey.


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1 comment

Hi My husband bought me one of your breath meters via amazon last week my initial reading was 3.5 and i was very happy but every test since has recorded a reading of 9.95 , i am not diabetic and don’t have ketoacidosis . can you tell me any reasons why i am getting this reading consistantly i test 3-4 times a day as instructed ,always first thing in the morning and before i eat.
Do you think it may be broken ?


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