Do Ketone Test Strips Go Bad?

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Ketone Test Strips go bad after being opened and exposed to the air.  A humid storage location, like a bathroom, will make them go bad even faster. Once opened, Ketone Test Strips will last 30 to 90 days.

Expiration Date on Ketone Test Strips

Every bottle of test strips, regardless of the brand, has an expiration date that is roughly two years after their manufacturing date. But this date is nearly worthless.

The expiration date on the bottle refers only to an unopened bottle. Once you’ve opened that bottle, that expiration date means nothing!

How quickly do they go bad after being opened?

The strips tend to last two to three months once opened, though I have had them go bad in less then five weeks!

With two people using the strips, we have only finished off one bottle in the years we’ve been doing keto.  That was our very first bottle that we bought when we were first starting keto and peeing on a test strip all the time just because we were excited and didn’t know what we were doing.

Here is my collection of articles and resources for starting a keto diet quickly and easily.

Every bottle since then, we’ve tossed with more than half of strips remaining.

How do you know when they’ve gone bad?

You know that your test strips have gone bad when they just quit working.  No matter how keto you’ve been, peeing on bad strips will always show zero ketones.

Just keep this in mind as you are starting your new keto diet. At some point a few months from now you’re going to wake up, pee on the stick and see no ketones and you’ll naturally want to freak out a little.

For that inevitable day, remember that ketone strips do go bad and just have an extra unopened bottle on hand (here is an affiliate link to the brand we usually buy on Amazon) when you need the comfort of a purple urine strip.

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How can you make your ketone strips last longer?

It’s air and humidity that makes them quit working, so keep the lid on tight and maybe store them outside of your humid bathroom.

You also don’t have to keep testing with the urine strips. They are a great tool for beginners as a way to identify whether you’ve achieved ketosis. However, along with their short shelf-life, they are not an accurate way to measure the amount of ketones you are producing.

Once you’ve been Keto for a while and you know how you need to eat to be in ketosis, the information you gain from the urine strips is minimal and you don’t need to keep using them.

If you truly want more information about your ketone production and how various foods effect your level of ketosis, consider blood ketone meter. They are pricey but give much more accurate data. Here is an affiliate link to the Keto Mojo Blood Glucose Meter, which is the one we use in our home.

Disclaimer: While I have been keto for over a decade and have guided thousands of people through starting a keto diet, I am neither a licensed nutritionist nor a medical professional. I never prescribe diets.  I only share my personal experiences and those of my clients for informational purposes only.  Nutrition details are provided for informational purposes only, and should not be considered medical nutritional data. You should consult your medical professional before making any major changes in the way you eat.


Stacey Davis

I am the co-founder of Advantage Meals along with my wife, Angela Davis. Together we run a Meal Solutions Business we created called Magic Meals Home Delivery. In April of 2018, we launch to help others thrive.

7 thoughts on “Do Ketone Test Strips Go Bad?

      1. I have a bottle in my bathroom cupboard and as I restarted Keto again yesterday I thought I’d use one. Didn’t expect it to work but it showed ketones. It was halfway between the first light colour and the last dark one. Can I really be in ketosis that quick?

        1. Switching between burning sugar and fat is a skill. As you practice it, you’ll become more fat-adapted and the transition between fuel sources becomes easier. Yes, you really can be in Ketosis that quickly. This is our natural state.

  1. Great information thank you 🙏 I noticed myself that once opened the stix stop showing correct results after being open for a couple of months … when I order new ones they show deep purple as they should but the old ones hardly change colour .. very helpful thank you 😊

  2. Bruh, I’m such a moron. I’ve been doing keto for over a week. I started out with 48g of carbs a day and the keto strips showed nothing. I reduced to 30g and still nothing. I’ve lost 7 pounds already and have no clue what is going on. Then I remembered, my strips were opened 6 months ago. Going to buy new strips. Doh!

  3. Thanks for all the great information. I used an old bottle to test with they didn’t seem to be working so I came here to get information on whether these strips go bad or not. I never knew they go bad. Thanks

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