Dexcom vs. FreeStyle Libre: How Do These Continuous Glucose Monitors Compare?

People living with Type 1 diabetes, and many with Type 2 diabetes, monitor their sugar (glucose) levels at home. This can be done with two devices: a blood glucose monitor (glucometer) or a continuous glucose monitor (CGM).

Both devices display glucose levels, but CGMs can help make managing diabetes easier. CGMs give a broader picture, improve safety, and connect with other smart devices such as smartphones. About half of those living with Type 1 diabetes use CGMs as their primary way of monitoring glucose levels.

If you’re interested in using a CGM, you might have questions about how they work and how to choose between two of the most well-known brands — FreeStyle Libre and Dexcom. Let’s discuss.

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What is a continuous glucose monitor (CGM)?

CGMs are wearable devices that track glucose changes around the clock. Instead of checking blood sugar multiple times a day, CGMs provide a steady stream of information. With real-time continuous results, you’ll get hundreds of readings every day. This can help you to predict and detect lows and highs, and identify patterns over time.

Glucose levels are always changing. Knowing yours is important, especially if you take insulin. CGM results can help you make informed choices about medication, foods, and activities. Plus, sharing CGM data with your diabetes care team is really easy — and they can suggest adjustments, even between appointments.

Many CGMs are available, including:

• Dexcom G6

• Dexcom G7

• FreeStyle Libre 2

• FreeStyle Libre 3

They all work differently but have similar functions.

How do continuous glucose monitors work?

CGMs, such as Dexcom and FreeStyle Libre, work by regularly tracking your glucose levels. Each system comes with a wearable sensor. The sensor uses a microneedle under your skin to detect glucose levels. Placement and wear time vary between devices. CGMs measure the amount of glucose in the fluid under the skin, not from the blood like a glucometer.

Getting your results

Readings from the sensor are sent wirelessly to a receiver by a transmitter. With some CGMs, the transmitter and sensor come already assembled. Other CGMs require you to connect the sensor and transmitter during the insertion process.

EXPERT PICKS: WHAT TO READ NEXT

• More about CGMs: Experts discuss how continuous glucose monitors (CGMs) work and how they can help you manage your glucose (sugar) levels.

• How much are CGMs? Prices vary depending on the model. Learn how much CGMs cost with and without insurance.

• Are CGMs available OTC? Yes, but they’re not right for everyone living with diabetes. Learn more about over-the-counter CGMs.

There are three options when it comes to setting up a CGM receiver. You can use a touchscreen reader, smartphone app, or compatible insulin pump. You’ll be able to view your glucose data on these devices. Trending data, alarms, and glucose patterns from CGMs can help you stay on track with your glucose goals.

Good to know: Certain smartwatches can also show your glucose readings. For instance, the Dexcom G7 can connect directly to certain Apple Watches. This allows the watch to show glucose readings even if you’re not near your phone.

What happens if my blood sugar is out of range?

Some CGMs can alert you if your glucose is too high or low. It’s important to know that not all devices have this alert system. If this function is available, your reader, phone, or insulin pump will alert you. You set the type of alert (such as a beep or vibration). This can offer an extra layer of safety, letting you know what your glucose level is and where it’s heading.

A CGM can be used along with, or instead of, a glucometer. But it’s important to know that a CGM can have a lag time. This is because it can take a bit of time for the glucose level in your tissues to catch up with the glucose level in your blood. If you’re having symptoms of high or low blood sugar, you should always confirm your level with a glucometer.

What are the differences between Dexcom and FreeStyle Libre?

Dexcom and Abbott are the manufacturers of two very well-known CGM devices. Dexcom makes the G6 and G7 models. The G7 model offers sensors with two different lifespans: a 10-day sensor and a 15-day sensor.

Abbott makes the FreeStyle Libre 14 Day, FreeStyle Libre 2, and FreeStyle Libre 3 systems. The Libre 2 and Libre 3 systems have two sensor options: original and Plus models. The original sensors are being phased out. So eventually, only the Plus sensors will be available. But it’s possible you may still receive the original sensors until they’ve been discontinued.

These CGMs are factory-calibrated. So, you don’t need to enter a blood sugar reading taken with a glucometer to keep your CGM accurate.

Each model has water-resistant sensors and transmitters, meaning you can swim and shower with it on. All models also allow you to view your data with a helpful graph on the reader, so you can see your glucose trends throughout the day.

But CGM devices differ in several ways: how glucose readings are sent to the receiver, whether they provide alerts for high or low sugar levels, and how often they need to be replaced. Let’s review seven notable differences among devices.

1. Who can use it?

The Dexcom G6 and G7 (10-day sensors only) are currently FDA-cleared for adults and children as young as 2 years old. The G7 15-day sensors are cleared for use only in adults ages 18 and older.

The Libre 14 Day system is only for adults ages 18 and older. The original sensors for FreeStyle Libre 2 and Libre 3 are cleared for adults and children ages 4 and older. But the Plus sensors can be used by adults and kids ages 2 and up.

2. Warmup times

After you insert a sensor, CGMs have a warmup period before they start working. While this time varies among CGMs, it can take between 30 minutes and 2 hours. You’ll have to use a glucometer to check your glucose during the warmup period.

The Dexcom G6 takes 2 hours to start tracking your glucose. The G7 15-day model has a 1-hour warmup period. The G7 10-day sensor model takes 30 minutes — the shortest warmup period of all CGMs. The FreeStyle Libre 14 Day, Libre 2, and Libre 3 systems take 1 hour.

3. Length of use

Sensor lifespan is another notable difference among the various CGM models.

Once the sensor is inserted, Dexcom G6 and G7 10-day sensors can last for up to 10 days. The G7 15-day sensor can last for up to 15 days.

The FreeStyle Libre 14 Day system has sensors that last for up to 14 days. The original Libre 2 and Libre 3 sensors also have 14-day lifespans. But the Libre 2 Plus and Libre Plus sensors can last for up to 15 days.

4. Frequency of readings

Dexcom G6 and G7 (including both 10- and 15-day sensors) are what’s known as real-time CGMs. This means they automatically update your reader, smartphone app, or compatible insulin pump with your new glucose levels. These devices send results to the receiver, app, or insulin pump every 5 minutes.

FreeStyle Libre 3 (including original and Plus sensors) is also a real-time CGM device. It sends readings to your smartphone app every minute.

FreeStyle Libre 2 (including original and Plus sensors) takes a reading every minute, and FreeStyle Libre 14 Day tracks your glucose every 15 minutes. However, these systems are known as flash glucose monitors or intermittently scanned monitors. This means the device only transmits glucose levels to the reader when you scan the sensor.

5. Low blood sugar alerts

The Dexcom G7 (both 10- and 15-day sensors) has customizable alerts for out-of-range glucose levels. You can set alarms to vibrate or temporarily silence them. It's important to look at your receiver during this time instead. You will not receive alerts for low and high levels (vibrations or beeps) during this time. But if you have an urgent low result, an alert will sound if you don’t respond to the vibration.

Dexcom G6 and FreeStyle Libre 3 (original and Plus sensors) have optional alerts for out-of-range glucose readings. But they also have special alarms, which you can’t turn off, to indicate dangerously low glucose levels.

FreeStyle Libre 2 (both original and Plus sensors) has alerts for out-of-range results. But alerts, including those for very low glucose, are optional and can be silenced if you’d prefer.

The FreeStyle 14 Day system is different in that it does not have alerting capabilities. This can be a big concern because low glucose levels (hypoglycemia) can be life-threatening. This is especially true if you have a hard time telling if your glucose is low (hypoglycemia unawareness).

6. Food logging

Both Dexcom and FreeStyle allow you to log the foods you eat in their apps. Doing this can help you track glucose trends and patterns over time. But the Dexcom G7 has a unique feature that can make it easier and less time-consuming to track the foods you’re eating.

Using the G7 smartphone app, you can take a picture of what you’re going to eat. The app uses artificial intelligence (AI) to identify the food and its likely ingredients. The app then logs this as it would if you manually entered these details.

7. Insulin pump compatibility

An automated insulin delivery (AID) system is a type of insulin pump that can help make using insulin easier. AID systems automatically adjust insulin doses in response to CGM readings. This can help improve the time spent in your target glucose range. Not all insulin pumps have these capabilities. But when they do, it helps to lighten the daily burden.

The table below highlights which AID systems are compatible with the Dexcom and FreeStyle Libre systems as of December 2025.

*Only the G7 10-day sensors are currently compatible with AID systems. But it’s expected that the 15-day sensors will be AID-compatible in the near future.

**This AID system is only compatible with Dexcom G7 sensors with a manufacturing date of 2024 or later. This information can be found on the side of your sensor package above the expiration date. Ask your pharmacist if you need help finding the manufacturing date.

Dexcom vs. Freestyle Libre cost

The average cost of a CGM system without insurance is estimated to be between $1,200 and $3,600 per year. Depending on which brand you’re purchasing, you may have two or three separate items to pay for. All CGM systems discussed in this article require a prescription.

The table below provides information on the average costs of the different components for the Dexcom and FreeStyle Libre CGM systems. Keep in mind that you can use Dexcom’s or FreeStyle Libre’s smartphone apps as the CGM’s receiver. So you may not need to purchase a standalone reader.

Are both Dexcom and FreeStyle Libre covered by insurance?

While this depends on your personal insurance plan, many types of insurance — including Medicare — now cover CGMs for people with diabetes, similar to how they cover glucometers. It’s possible that your plan may only cover one brand, so it’s best to contact your insurer to ask for details.

If you don’t have diabetes and are interested in using a CGM, it’s unlikely your insurance will cover these devices. This may also be the case if you have prediabetes or gestational diabetes (diabetes during pregnancy). But there are still some ways to save and avoid paying the full retail price.

How to save on a continuous glucose monitor

There are ways to save on diabetes testing supplies, including CGM devices. GoodRx can help you navigate ways to save on your Dexcom or FreeStyle Libre prescription.

How to save on Dexcom

Here are some ways to save on the Dexcom G6 and G7:

• Save with GoodRx. GoodRx can help you save $220 or more off the average retail price of G6 or G7 sensors and $240 off the price of a G7 receiver. Dexcom G7’s price at certain pharmacies is around $175 for 3 sensors with a free GoodRx discount. Dexcom G6’s price at certain pharmacies is also around $175 for 3 sensors with a free GoodRx discount.

• Save with a patient assistance program. If you’re uninsured or underinsured, you may be eligible for Dexcom’s patient assistance program, which may offer the device for free or at a reduced cost.

How to save on FreeStyle Libre

Here are some ways to save on FreeStyle Libre:

• Save with GoodRx. GoodRx can help you save over 30% off the average retail price of the sensors. The price of FreeStyle Libre 3 Plus sensors at certain pharmacies is about $85 with a free GoodRx discount. The price of FreeStyle Libre 2 Plus sensors is also around $85 with GoodRx.

• Save with a copay card. If you have commercial insurance or are uninsured, you may be eligible to pay $75 or less for FreeStyle Libre 3 Plus or Libre 2 Plus sensors using a savings card from the manufacturer.

• Save with a free trial. Abbott offers a free 15-day trial of the Libre 3 Plus sensor with the MyFreeStyle program. If you qualify, you’ll receive a voucher for one free sensor. You can present the voucher at your preferred pharmacy.

Who is a continuous glucose monitor good for?

A CGM can be helpful for anyone living with diabetes. But it’s even more beneficial for those missing early warning signs of low glucose. There’s also growing interest in whether CGMs can be good for people without diabetes, but this is less clear — and there are specific CGMs for this population, such as FreeStyle Lingo.

People with diabetes

If you have diabetes, a CGM can help you better manage your glucose over time and monitor for trends. You’ll notice what activities and foods are associated with your highs and lows.

Other benefits of CGMs include:

• Helping people with diabetes meet their hemoglobin A1C (HbA1c or A1C) target goals

• Having the ability to measure your time in range (TIR) — meaning the percentage of time your glucose is within your target range

• Potentially lowering the risk of low glucose (hypoglycemia)

• Potentially lowering the risk of diabetic ketoacidosis (DKA) — a life-threatening complication that can happen when glucose levels are very high

People without diabetes

People without diabetes have started using CGMs to monitor their glucose levels and:

• Guide diet or exercise plans

• Track fitness patterns

• Build athletic endurance

• Maintain higher athletic performance levels

There’s no evidence about whether using CGMs for people without diabetes has any long-term health benefits. But an ongoing clinical trial is researching one possible benefit. This study will look at whether people without diabetes can lose weight more effectively by using CGM devices.

Why trust our experts?

Written by:

Timothy Aungst, PharmD

Timothy Aungst, PharmD, has worked in pharmacy practice for a decade. He has served as an associate professor of pharmacy practice, a clinical pharmacist in outpatient cardiology management, and now in home healthcare.

Edited by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

Reviewed by:

Jewels Doskicz, RN, BA

Jewels Doskicz, RN, is an Arizona-based registered nurse with more than 20 years of hospital-wide clinical nursing experience. She has spent over a decade in medical writing and editing, with a focus on diabetes and autoimmune disease.

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