The first disposable breath ketone test has arrived

The Metron breath ketone test

Do you want a simple way to check for ketosis, without a urine or blood test? It’s also possible to check you breath for ketones (acetone). This has already been possible for some time with the Ketonix reusable breath analyser (costing $149).

Now the Ketonix is joined by the just-launched disposable test Metron, which can be ordered via Amazon ($28 for 10 tests).

Metron is cheaper if you only want to do a few tests (up to 50 tests), but the reusable Ketonix is cheaper if you want to do more tests than that – testing is free once you have one.

At some point we may do a test of Ketonix vs. Metron. Would you find that interesting? Or do you already have your own experience comparing these two devices? Please leave a comment.


Lose Weight by Achieving Optimal Ketosis


  1. Chris the Barbarian
    Don't really see the point of testing for Ketone Bodies in Breath/Serum/Urine, unless you are doing it for treating epilepsy and need to be sure that you are in deep nutritional ketosis.

    My own meter for success is my Mirror ;).

  2. Nancy
    I would be interested in a comparison. My Ketonix is more like a random number generator for me. I can't get it to correlate with my blood ketone measures. I don't really measure anymore, but I would be interested in how this matches to Ketonix and the blood ketone measurements.
  3. greensleeves21
    Hi Nancy:

    Since the blood & urine ketone tests measure different substances, why should they correlate or be the same? Many people have this expectation, which has no current scientific basis, and it seems to be one of many myths around ketosis. Your body uses the two ketones differently for different purposes & becomes more efficient with them over time. So again, why should they be equivalent or related? Would really love to hear your science on this, if you have some new insight. Thanks.
    No Andreas, I don't think a comparison will be useful - it's like comparing a hacksaw to a cocktail shaker, really. They do different things on different substances. :D Best wishes. (I live at about 4.2 on the blood meter BTW, with lows of about 2.1)

    Replies: #6, #10
  4. Apicius
    I would love to see a comparison test! I used to use the urine and blood testing kits. Both worked for me...with the blood test kit being a bit more reliable. But, I don't like pricking my finger, so I would love to know how well these two ketone breath testers work.
  5. Lucy
    What would really be useful is a comparison test trying to correlate breath readings and blood readings. My only gripe with the Ketonix, which I have, is that it doesn't correlate straightforwardly with blood ketone levels. There is only one piece of research by Ryan Scott comparing the two, at . More would be good. I use the Ketonix to check if I'm in ketosis because it means I can rely on my blood sugar levels being more consistent.

    And the Ketonix is astronomically cheaper than ketone strips. Only Type 1s who have to check they are not going into acidosis use those.

  6. Steven
    Greensleeves21.. How do you achieve this high number? I'm eating about 20 carbs per day with high fat mct and I don't use artificial sweeteners or anything like that, but my typical readings are .4 to .9 with an all time high of 2.1... But I'm never hungry and I am losing weight, and my blood glucose levels are excellent (fasting is a bit high, but postprandials are fantastic with an A1C of 4.7)... Do I need to get the numbers up to burn fat more efficiently? Or is my body just using the excess? Sorry to go on and on but sounds like you know what's going on lol...
  7. 1 comment removed
  8. Francoise
    I currently use the KetoCalc app from to evaluate whether the meals I plan are ketogenic. By inputting the carbs, protein, and fat grams it calculates the macronutrient percentages and also gives you the total kCal number if that is something you also watch. Jimmy Moore mentioned it in one of his KetoTalk podcasts. I was able to download the app for free but now there is a charge of $9.99. I find the app very useful. If you cannot fork over the money for a glucose/ketone monitor, my opinion is that this app is worth the money. It also works with MyFitnessPal app which I use to plan my meals.
  9. Francoise
    An add on to my previous comment. I forgot to mention the most important piece of information! By inputting the grams for carbs, protein, and fat, the app shows you the ketogenic value of the meal. If the meal is not ketogenic enough, you can tweak your meal plan to obtain the desired ketogenic value.
  10. Leon Fairbanks

    Both devices claim to measure breath acetone. You seem to be have confused metron with blood and urine tests.


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