How to Use Ketone Strips to Stay in Ketosis

If you are new to the world of low carb, you may have come across people talking about ketone strips or “ketostix” to see if they are in ketosis. These are small strips to test your urine to see if you have ketones in it. It is a roundabout way to see if you are in ketosis. Here is a guide to your most common questions about how to use ketone strips and if they are right for you!

Ketone Strips FAQ

What Are Ketone Strips Used For?
Ketostix are used to help track when someone is in ketosis. Sometimes people use them to see how many carbs they can consume and stay in ketosis. For most people this range is from 40-55 net carbs a day. For other, it can be as low as 20 carbs per day. Also, it can be used to help determine what foods may interfering with ketosis. For some people, dairy products, artificial sweeteners, or high fiber foods (giving a high carb content, but low net carb result) will take them out of ketosis. Using these strips can help one figure out what the problem is if they are not staying in ketosis or losing weight.

How To Use Ketone Strips:
You take a strip and dip it into your urine. Generally it is better to dip it into a cup with urine in it, rather than passing through your urine stream. This is because if your stream is too strong, you could potentially wash all the reagent off of the strip and get a false negative result. Either way, dip it, and remove immediately. Usually the bottle will tell you how long to wait, but as a general rule, you will see your results in seconds. After a minute, the results are no longer valid.

How Accurate Are They?
They are very accurate at showing if you are passing ketones in your urine, so the rate of a FALSE positive is very low. However, you can be in ketosis WITHOUT having ketones in your urine. If this is the case, you would get a false negative. This is because you are measuring ketones in your urine, not your blood. Some people use their ketones more efficiently, and  make less of them, therefore they don’t “spill” into the urine.  Also, as a person spends more time in ketosis, such as several months, lower levels of ketones are detected in the urine, even while they are still burning fat and following the ketogenic diet well.

What Brand Should You Use?
There is no specific brand that is superior. I personally like SmackFat, which has 100 strips and has a 4.5 star rating on amazon. You can check it out here: Smackfat Ketone Strips {affiliate link}

What Are Other ways to Know You Are in Ketosis?
Ketones can be detected in the breath, blood or urine. Testing the urine with ketone strips is generally the quickest and easiest method. They make disposable breath ketone tests, which you can check out here: Disposable Breath Ketone Test {affiliate link} They also make blood ketone meters.

What is The Best Way to Detect Ketosis?
The most accurate way to detecting ketosis would be a blood test. They now make blood meters that measure ketones in your blood similar to a blood sugar test. In fact most of the monitors made can do both, as they are designed for diabetics. You simply prick your finger and put a drop of blood onto the reagent strip and plug it into the meter. I personally like the Precision Xtra Blood Glucose and Ketone Monitoring System {affiliate link}

What Do The Darker Colors Mean?
Ketone strips usually range from white/cream color which is negative, to purple, which means large ketones are being passed in the urine. But a darker strip does not correlate with “more” ketosis. You are either in or out of it. A purple strip is more of a sign of DEHYDRATION. You may notice your back hurts more when the strips are purple. This means your kidneys are under stress. Remember that ketosis puts you in somewhat of a water wasting state. It is important to stay hydrated in this process!

ketone color





Happy Ketosis! ~HealthyGirl

P.S. Have I answered all your questions about ketone strips? Comment below!


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4 thoughts on “How to Use Ketone Strips to Stay in Ketosis

  1. I have tested positive and negative on the strips in a 24 hour period what does this mean? like I can wake up and my first urine will be negative but after a meal or fasted cardio Im pink ( I drink a gallon of water a day so I do not think Ill ever be dark purple). Are you in ketosis all day or just certain times a day? I can urine test around 5pm and be negative again then test at 8pm and be positive. Can you not be in ketosis but still test pink?

  2. You mention that ” purple strip is more of a sign of DEHYDRATION. You may notice your back hurts more when the strips are purple. This means your kidneys are under stress.” But, why doesn’t it say that instead of level of ketone in you system. Your explanation doesn’t make sense to me. Please explain how what you are saying coincides with what is on the bottle where it shows ketone levels.

    • Wow just wow not sure why this is so confusing to you. When you are dehydrated your urine if more concentrated. When you are well hydrated your urine is more diluted. Take a gallon of water and add 1 tablespoon of salt. If you taste it there will be a barely if any noticeable taste of salt. Boil off 90% of that water and taste it again and it will be very salty. They strips are only capable of detecting the quantity of ketones in the sample it received.

      So say your bladder is currently full with 8 oz of urine and has quantity X of ketones. You will get a certain mark on the strip. The next day if your drank more water and your bladder now has 16 oz of urine and the same X quantity of ketones the sample on the strip will now register 1/2 as much.

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