Keto Strips Turning Gray? Here’s Why and What It Means

Posted April 29, 2020 by Clint Kelly - See Editorial Guidelines

Keto strips are used by diabetes patients and for those looking to achieve weight loss to check the level of ketones in the urine. Whether used for diabetes or weight loss, the product is used to check the number of ketones in the body to monitor and control diabetes or weight loss.

One of the most confusing things about keto strip is the different colors they indicate and what they mean. In some cases, keto strips can turn a gray color. So, in this article, we hope to give a clear understanding of what the gray color on a keto strip means and what other colors on keto strips mean.

Here’s the quick response, then we’ll head into a bit more detail.

Why do keto strips turn gray? There is no exact reason why keto strips turn gray. Many believe that keto strips turn gray when they pass the expiration date. In general, keto strips are believed to expire 6 months after opening. However, sometimes, keto strips turn gray when they come in contact or interact with heat and moisture.

The color of the Keto strips indicate the amount of ketones (ketone concentration) in the urine. Usually, keto strips come with a well-detailed leaflet or chart, which indicates the correlation between the color and level of ketones.

However, strangely, many users of keto strip have experienced their keto strips turning gray. And to those who are unaware, the keto strip color guide doesn’t show a gray color or say what this color means.

Why Does Keto Strip Turn Gray?

Keto Strips Turning Gray

The general rule is that the more the ketones are there in the urine, the most it is likely to cause diabetic ketoacidosis (DKA), a complication of diabetes that can lead to a coma or even death.

So, when seeing this in the color palette, the lighter color, usually starting from beige and cream, means that the ketone concentration is low. If the strip turns a darker purple, then it means the level of ketones is high. This may indicate for a person with diabetes that their blood sugar levels are too high.

So, if a person gets a strip that turns a darker gray, then they may believe that it is indicating high blood sugar, or that they are in ketosis.

Although there’s no apparent reason for a keto strip turning gray, many say that the reason for this has to do with the expiration date. Usually, keto strips only have up to a six-month life span after opening.

This means that keto strips should be used within six months of opening. So, many health professionals have advised that using open keto strip after these 6 months may give false readings. Therefore, it is recommended to discard the container of keto strips if it has been longer than 6 months since first opening it.

One best way to make sure it’s used within the six months is to write the date of opening the keto strip container.

Writing the date of opening on the box will remind you how long it’s been opened and to discard once the 6 months pass.

Some also say that the temperature, moisture, and the place it’s stored can make it expire much sooner due to interactions, causing the keto strip to turn gray. This means that keto strips can lose their coloring capacity, making them turn gray when they are stored in direct heat, in high moisture areas, or around other inappropriate places.

Some individuals may even have concerns when the keto strips don’t change any color. So, now let’s see what it means when keto strips don’t change color.

What Does It Mean When Keto Strips Don’t Change Color or Have a Darker Color?

Not seeing a color change in the keto strips doesn’t necessarily mean that one is not in ketosis. Not seeing a change in the color just means that the strips are not detecting the ketones in the urine.

The same applies to keto strips that happen to turn gray. Gray ketone strips don’t give a proper reading because it may not be able to detect the ketones that it’s looking for in the urine.

If one uses a keto strip that turns gray, they should not immediately make an assumption on whether or not they are in ketosis. One option, in this case, is to purchase and use a brand-new box of keto strips. If you have diabetes and are testing for ketones because you have symptoms of diabetic ketoacidosis (DKA), then call your doctor right away.

It is dangerous for a person with diabetes to enter ketosis. So, a person with diabetes, that uses a keto strip, and it comes back as a dark purple, may become worried. However, those that are on the keto diet looking to lose weight may strive to see this color on their keto strip.

Therefore, if you have diabetes and the strip is reading a high ketone level, you should compare this with your blood sugar readings. If your blood sugar has been consistently high, then you may be in the beginning stages of diabetic ketoacidosis. If this is the case, then call your doctor and seek medical attention.

The keto strips may give you a false reading if you are dehydrated when you do the test. Make sure that you are well hydrated prior to using a strip.

Are the Colors on Keto Strip Accurate?

Keto Strips Turning Gray

It is helpful to know if the colors on a keto strip are accurate, as it can help you determine if your health is headed in the right direction.

Unfortunately, keto strips only measure the ketones that are excreted by the body. This means that these strips only measure the excess ketones which the body couldn’t use. This also means that it doesn’t take into account the levels of ketones in the blood.

So, in this case, even if the keto strips show a lighter color meaning low ketones concentration, in reality, one may have more ketone concentration than what these strips show. This is also one of the reasons why many health professionals encourage blood ketone measurement because it gives a more accurate and precise measurement of ketones.

Ultimately, urine keto strips will give you an overview of the ketone concentration in your body. The most accurate ketone reading will come from your blood, though.


We hope this has been useful in understanding more about keto strips turning gray and the overall use of the strips.

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