What to Know About the FreeStyle Libre Continuous Glucose Monitor

The FreeStyle Libre system is a continuous glucose monitor (CGM) worn on the upper arm that provides real-time blood sugar (glucose) readings. It is intended for use by people who have type 1 diabetes or type 2 diabetes, especially those who take insulin.

This article looks at how the FreeStyle Libre system works, the benefits and limitations of the device, and when traditional fingerprick testing may be needed.

FreeStyle Libre sensor on a patient's arm

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How the FreeStyle Libre Works

The FreeStyle Libre system provides real-time glucose readings every minute, 24 hours a day. There are two systems to choose from:

  • Freestyle Libre 14-day system (approved for adults 18 and older)
  • Freestyle Libre 2 system (approved for adults and children 4 and older)

The FreeStyle Libre is a newer-generation CGM that doesn't require a bulky transmitter. Instead, a small, water-resistant sensor with a tiny probe is placed on the back of the arm using the provided applicator.

The FreeStyle Libre tests the fluid in the space around cells, which is just as effective for glucose monitoring as blood from capillaries (small blood vessels, such as in your fingertip).

One hour after applying the sensor, the system is ready to go. The sensor takes a glucose reading every 60 seconds. A separate reader device remotely captures and records the readings on demand. You can then view the results individually or see how glucose levels trend over time.

To get a reading, place the reader within 1.5 inches from the sensor. You can scan the sensor as often as you'd like, but it is recommended that you perform a scan at least once every eight hours. (There are FreeStyle Libre apps available in the App Store and Google Play that can turn your smartphone into a reader).

The sensor can be worn for up to 14 days and store 90 days' worth of results. After 14 days, the sensor stops working and needs to be replaced.

The FreeStyle Libre 2 is also equipped with an alarm to notify you if your glucose levels are too high or too low. The original FreeStyle Libre 14-Day does not have this feature.


The FreeStyle Libre consists of a remote reader and a waterproof sensor that is attached to the back of your arm. To check your glucose, the reader is placed immediately over the sensor. The reader can capture and store up to 90 days' worth of glucose readings.


CGM devices like the FreeStyle Libre offer advantages over traditional fingerprick monitoring. Studies have shown that people with diabetes who test their blood frequently have steadier glucose levels. They also have a lower A1C, which is a measurement of long-term blood sugar control.

CGM devices are also better at preventing hypoglycemia (low blood sugar), including nighttime hypoglycemia.

With the FreeStyle Libre system, you don't need multiple fingerprick blood draws each day to ensure your glucose remains within the normal range.

Aside from being more convenient, the device is pain-free. This may motivate people to take their glucose readings more frequently.

Another unexpected advantage of the FreeStyle Libre system is that it appears to reduce the cost of diabetes care. According to a 2020 study published in US Endocrinology, the FreeStyle Libre system cut the annual cost of medical care for people living with diabetes by more than 50% compared to users of fingerprick tests.


Compared to fingerprick tests, continuous glucose monitoring devices like the FreeStyle Libre help people keep their glucose levels more stable, prevent hypoglycemic attacks, and lower A1C. Some studies suggest the device can reduce the annual cost of diabetes care.


The FreeStyle Libre system does have some limitations, however.

Among them, the original FreeStyle Libre 14-Day is not equipped with an alarm feature and may not be the best choice for people with hypoglycemia unawareness. This is a condition in which people do not realize when their blood sugar levels have dropped severely.

Although the FreeStyle Libre system had an accuracy of around 92% in studies, inaccuracies can sometimes occur. This can happen when there are rapid changes in blood glucose, such as after eating, taking insulin, or exercising. Severe dehydration can also affect the readings.

Because of this, the Libre FreeStyle reader has a built-in blood glucose meter. This allows you to perform a fingerprick test to ensure that the CGM reading is accurate. This is especially useful if the reader says that your glucose levels are either too high or too low.

The FreeStyle Libre sensor is waterproof but should not be submerged for more than 30 minutes. Unused sensors can be stored at room temperature in a dry place.


The FreeStyle Libre 14-Day does not have an alarm feature and may not be as suitable for people with hypoglycemia unawareness. The device may also be less accurate if you are severely dehydrated or have just finished eating, exercising, or taking insulin.

Cost and Availability

FreeStyle Libre systems are available in pharmacies with a prescription. The retail price of the sensor is around $85 for the FreeStyle Libre 14-Day and $130 for the FreeStyle Libre 2. The reader costs around $65 (or free if you download the app onto your smartphone).

For people with private insurance or Medicaid, expect out-of-pocket costs of between $40 to $75 per month. The product is fully covered by Medicare for those who qualify.

In addition, the FreeStyle Libre system uses test strips called Precision Neo test strips for fingerprick testing. A box of 50 individually wrapped strips costs around $20. Using other test strips with the built-in meter may produce an error.


The retail price of each 14-day sensor is between $85 and $130. With insurance, the out-of-pocket cost may be as low as $0 to $75 per month.

Comparison to Other Devices

The FreeStyle Libre is referred to as a flash glucose monitoring system. Unlike other CGMs, like the Medtronic Guardian 3 and Dexcom G6, the FreeStyle Libre checks glucose levels every minute rather than every five minutes. It can also be worn for 14 days as opposed to seven days for the Medtronic Guardian 3 or 10 days for the Dexcom G6.

The FreeStyle Libre system does not require fingerprick calibrations. And, because there is no transmitter, the system costs less than other CGMs.

Whereas other CGM sensors can be placed on the belly and buttocks, the FreeStyle Libre is only approved for use on the back of the arm. If placed in other areas, the sensor may not work properly.

A newer CGM called the Eversense system offers continuous 90-day glucose monitoring. But sales of the device were halted in 2020 due in part to the COVID-19 pandemic but also to the fact that the device has to be implanted by a doctor.


In terms of cost, availability, and ease of use, the FreeStyle Libre is superior to other FDA-approved CGMs like the Medtronic Guardian 3, the Dexcom G6, and the Eversense system. The only drawback is that the sensor can only be placed on the back of the arm.


The FreeStyle Libre is a continuous glucose monitoring system used to check blood sugar in people with diabetes. It is comprised of a waterproof sensor that is worn on the back of the arm and a separate reader that records the glucose levels. The sensor is worn for 14 days and then replaced.

The Freestyle Libre system has proven effective in stabilizing blood sugar in people with diabetes while lowering both the A1C and the risk of hypoglycemic attacks. While effective, the FreeStyle Libre may be less accurate after eating, exercising, or taking insulin, and it sometimes requires a backup fingerprick test. Severe dehydration can also affect the results.

The retail price of the 14-day sensors is around $85 for the FreeStyle Libre 14-Day and $130 for the FreeStyle Libre 2. With insurance, the cost may be reduced to as little as $0 for some people.

Frequently Asked Questions

  • What is the FreeStyle Libre?

    FreeStyle Libre is a type of continuous glucose monitoring (CGM) device used by people who require insulin to manage their diabetes. The FreeStyle Libre 14-Day is approved for people 18 and over, and the FreeStyle Libre 2 is approved for adults and children 4 and over.

  • How does the FreeStyle Libre work?

    The FreeStyle Libre consists of a disposable sensor that is attached to the skin on the back of your arm for up to 14 days, as well as a separate receiver. It regularly monitors glucose levels in the interstitial fluids that surround cells beneath the surface of the skin.

  • How much does the FreeStyle Libre cost?

    For most people with private insurance, Medicare, or Medicaid, the FreeStyle Libre can cost between $0 to $65 per month. The most expensive aspect are the sensors, which can cost $130 per month. For those without insurance, the cost can be reduced with a manufacturer copay card.

  • How accurate is the FreeStyle Libre?

    The FreeStyle Libre system offers an accuracy of 92.8%, according to a 2019 study published in the journal Diabetes.

  • Where can I buy FreeStyle Libre?

    You can buy the FreeStyle Libre online and at many drugstores and supermarket pharmacies. You will need a prescription to purchase the device whether you have insurance or intend to pay out of pocket.

  • Can anyone with diabetes use FreeStyle Libre?

    As convenient as the FreeStyle Libre is, it may not be as accurate as traditional blood glucose monitoring. The sensors can also cause allergic dermatitis in some people. Talk to your doctor to see if the FreeStyle Libre is right for you.

  • Are there alternatives to FreeStyle Libre?

    In addition to the FreeStyle Libre, there are three other continuous glucose monitoring devices approved the Food and Drug Administration (FDA):

    • Dexcom G6 CGM: A skin sensor-based device approved for ages 2 and over
    • Eversense CGM: An implantable sensor device approved for ages 18 and over
    • Medtronic Guardian Connect: A skin sensor-based device approved for ages 14 to 75
  • How does FreeStyle Libre compare to similar devices?

    The FreeStyle Libre is cheaper than the Dexcom G6 and Medtronic Guardian Connect and does not need daily calibration. It checks glucose levels every minute rather than every five or more minutes for the other devices. On the downside, the FreeStyle Libre 14-Day does not have an alarm for high/low glucose levels.

12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Barbie Cervoni MS, RD, CDCES, CDN
Barbie Cervoni MS, RD, CDCES, CDN, is a New York-based registered dietitian and certified diabetes care and education specialist.