Dexcom CGM Explained
Dexcom G7 vs. FreeStyle Libre 3 and Libre 3 Plus: Choosing the Right CGM
Mar. 3, 2025 • 7 min read
The content in this article should not be taken as medical advice. Please consult with your healthcare provider regarding your individual health needs.
Technology has revolutionized diabetes management, giving people with diabetes new options that are easier, more accurate, and more advanced. This includes Continuous Glucose Monitoring (CGM) technology, which has empowered millions with diabetes to gain better control of their glucose levels and live happier and healthier lives.
But not all CGM systems are the same.
The Dexcom G7 CGM System makes it possible to get accurate glucose readings without fingersticks.* Other devices, such as the FreeStyle Libre 3 and 3 Plus system, can also provide a view into glucose levels without using a blood glucose meter. While Dexcom G7 and FreeStyle Libre 3 and Libre 3 Plus both support continuous glucose monitoring and management for those living with diabetes, the features and benefits of these systems aren’t equal.
Compared with FreeStyle Libre 3, the Dexcom G7 is more accurate,1 warms up faster,† and allows you to make treatment decisions in the first 11.5 hours of wear.*,2 In addition, Dexcom G7 is more affordable§,3 for most patients.
*If your glucose alerts and readings from Dexcom G7 do not match symptoms or expectations, use a blood glucose meter to make diabetes treatment decisions.
*If your glucose alerts and readings from Dexcom G7 do not match symptoms or expectations, use a blood glucose meter to make diabetes treatment decisions.
Since everyone experiences diabetes in their own unique way, and no two people have the same needs when it comes to CGM, let’s compare the pros and cons of Dexcom G7 with FreeStyle Libre 3 and 3 Plus to explore which system best fits your lifestyle and management goals.
What’s the difference between Dexcom G7 and FreeStyle Libre 3 and Libre 3 Plus?
Both Dexcom G7 and FreeStyle Libre 3 take glucose readings using a sensor worn on the body and sends them to a display device, so you can view glucose levels on your compatible‡ smartphone in the palm of your hand in real-time. Though there are some similarities between the two systems, they offer notably different glucose monitoring experiences.
See why Dexcom G7 is the CGM most recommended by patients4 and healthcare professionals.5
Benefits of CGM | Dexcom G72 | Abbott FreeStyle Libre 36 | Abbott FreeStyle Libre Libre 3 Plus7 |
The most accurate CGM1 | ✓ | ||
Predictive urgent low soon alert | ✓ | ||
Sensor warmup time† | 30 minutes | 60 minutes | 60 minutes |
Time before making insulin treatment decisions without fingersticks* | 30 minutes | 12 hours | 12 hours |
Most frequent out-of-pocket cost per month for most covered patients§,3 | $0 | $80 or more | $80 or more |
Wear time | 10.5 days includes 12 hour grace period | 14 days | 15 days |
Number of simultaneous Bluetooth® connections (phone, smartwatch, receiver or AID system) | 3 | 1 | 1 |
Available for integration with multiple insulin pumps and pens|| | iLet Bionic Pancreas Lilly Tempo Insulin Pen Omnipod® 5 Tandem Mobi System Tandem t-slim:X2TM insulin pump | iLet Bionic Pancreas | |
Ability to share glucose data¶ while connected to an AID system | ✓ | ||
Indicated for ages 2 and up | ✓ | ✓ | |
Direct to Apple Watch connectivity# | ✓ |
'If your glucose alerts and readings from Dexcom G7 do not match symptoms or expectations, use a blood glucose meter to make diabetes treatment decisions.
1. Accuracy and Overall Effectiveness
Dexcom G7 has the best accuracy of any CGM available,1 which means it has been shown to provide readings that are closest to clinical blood glucose readings. One way the accuracy for a CGM system is measured is by mean absolute relative difference (MARD). The smaller the MARD number, the higher the accuracy.
Dexcom G7 has a MARD (the standard measure of CGM accuracy) of 8.2%,2 while the FreeStyle Libre 3 has a MARD of 8.9%8-12 making Dexcom G7 more accurate.1
Using Dexcom G7 is also clinically proven to lower A1C8-12 over time. Dexcom G7 can even help you spend less time in your low range (hypoglycemia) and more time in your target glucose range.8-12
In terms of accuracy, if you are not using a CGM, you're likely used to using your blood glucose (BG) meter to get your glucose readings, so you should know there is a difference between a BG reading and your CGM readings, and they may vary slightly when you compare the two.
2. Price and coverage
Clearly defining cost and coverage can be a moving target, as insurance providers and Medicare can change their policies and stipulations.
Dexcom is the most affordable CGM brand at pharmacy.§,2 Most patients pay $0 for Dexcom G7 compared with $80 or greater for Freestyle Libre.§,2 Dexcom also offers help for Medicare coverage. With Dexcom G7, you get the best accuracy1 at a lower cost. *,3
Both Dexcom Savings Center page and FreeStyle’s Cost and Coverage webpage offers savings vouchers depending on your health coverage.
3. Real-time continuous glucose monitoring
Both Dexcom G7 and FreeStyle Libre 3 provide real-time glucose readings. Data is sent from both devices to a compatible smart device or receiver (reader) for you to view your current glucose value. Both systems also give you a trend arrow to show the direction your glucose is heading, and how quickly your glucose is rising or falling.
Dexcom G72 sends readings to your compatible smartphone every five minutes, and the receiver or smartphone can receive information up to 33 feet away. The Freestyle Libre 36 and Libre 3 Plus7 sends readings every minute from up to 33 feet away.
In addition, Dexcom G7 and FreeStyle Libre 3 both allow loved ones, parents and caregivers to monitor glucose levels remotely with real-time updates.
The Dexcom Follow app¶ enables up to 10 people to view glucose data and get alerts from their loved one's Dexcom G7 app on their own compatible* smart devices. This is ideal for individuals who need extra support managing their glucose.
Libre LinkUp, Frestyle Libre's version of the Follow App, enables up to 20 people to view glucose data and glucose alarms.
4. Painless sensor application and quick warm-up
Applying and changing the Dexcom G7 sensor and the Libre 3 or 3 Plus sensor is very similar. Both Dexcom G7 and Freestyle Libre 3 and Libre 3 Plus come with applicators that are pre-loaded with a sensor and are applied to the body, usually the back of the upper arm. This is usually painless for most Dexcom CGM users.**, 3
However, Dexcom G7 has the shortest warm-up time to start getting readings of any CGM system, taking just up to 30 minutes† from the moment the sensor is inserted to your first reading—this is half the time of FreeStyle Libre 36 and FreeStyle Libre 3 Plus7 which takes 60 minutes to warm-up.
This means with Dexcom G7 you can get your glucose readings and some extra peace of mind sooner.
5. Sensor wear, water resistance
Both Dexcom G7 and FreeStyle Libre 3 have discreet sensors about the size of a couple of stacked coins with Freestyle Libre 3 and 3 Plus being slightly smaller. Dexcom G7 is Dexcom's most comfortable and discreet sensor—60% smaller†† than its predecessor. Its small size and upper-arm wear location is comfortable and makes it easy to forget you're even wearing it.13
The Dexcom G7 sensor can be worn for up to IO days while the FreeStyle Libre 36 and 3 Plus7 can be worn for up to 14 or 15 days respectively. Dexcom G7 has a bonus 12-hour grace period at the end of the 10-day session, giving you some added flexibility to change out the sensor when it's convenient for you.
The Dexcom G7 sensor is also waterproof‡‡,3 in as much as 8 feet (2.4 meters) of water for up to 24 hours. This means you can feel more confident wearing your sensor while you're sweating, taking a long bath, or going for a swim. FreeStyle Libre 36 and 3 Plus7 are only water-resistant up to 3.2 feet (1 meter) and can't be immersed for more than 30 minutes.
6. Glucose alerts and alarms
Dexcom G7 and FreeStyle Libre 3 and 3 Plus both have alerts or alarms that can notify you when your glucose levels are high or low. Dexcom G7 has a wider range of customizable alerts designed to help you take proactive action to help increase time in your target range and decrease highs and lows.8-12 These include:
- Urgent Low Soon Alert — The predictive Urgent Low Soon Alert can warn users in advance (within 20 minutes) of a severe hypoglycemic event (55 mg/dL), which helps give you time to take appropriate action before a low glucose event occurs.
The FreeStyle Libre 3 and 3 Plus systems alert you when you reach high and low glucose thresholds, but not before. This may make it more challenging to anticipate the steps you need to take to avoid potentially serious lows.
- Delay 1st High Alert — Dexcom G7 is the only CGM with a Delay 1st High Alert designed to reduce alert fatigue and insulin stacking.1-2 Users can delay their first high alert and avoid getting another alert long enough for the insulin to have worked. You can also customize when you'd like to get high alerts, so you're only notified about high glucose after a period you specify.
The FreeStyle Libre 3 or 3 Plus system do not offer a Delay 1st High Alert.
7. AID/insulin pump compatibility
For some who have diabetes, using an Automated Insulin Delivery (AID) system or insulin pump paired with a CGM can be the best way to manage their condition. This pairing can make it easier to stay in range and remove some of the guesswork from insulin dosing. But compatibility varies depending upon which CGM you choose.
Dexcom G7 is the leader in AID compatibilitylI.3 and is compatible with the largest variety of AID systems, including iLet Bionic Pancreas, Omnipod 5, Tandem Mobi, and Tandem t:slim X2 insulin pump.
FreeStyle Libre 3 Plus is only compatible with iLet Beta Bionic Pancreas.
In addition, Dexcom is also the only CGM with Share and Follow¶ capabilities that work while using an AID system. Libre CGM systems can only connect to either the AID system or Libre LinkUp, not both simultaneously.
8. Direct to Apple Watch
Direct to Apple Watch connects the Dexcom G7 sensor directly to your Apple watch using Bluetooth. When Direct to Watch is active, your sensor sends CGM data right to your watch, so you don't need your phone nearby to see your glucose numbers.# View a list of compatible Apple Watches here.
The FreeStyle Libre 3 system does not offer Direct to Watch compatibility.
9. Support for more types of people
Dexcom CGM Systems are also indicated for a very wide range of people who live with Type 1 diabetes or Type 2 diabetes. Dexcom G7 can be used by children as young as 2 years old and can also be worn during pregnancy and for those experiencing gestational diabetes.
FreeStyle Libre 36 can be used by individuals 4 years old and up and is approved for use during pregnancy and gestational diabetes.
Freestyle Libre 3 Plus7 can be worn by children as young as 2 years old.
Find out if Dexcom G7 is the right CGM for you
Dexcom is the #1 recommended CGM brand by both doctors and patients.4,5 Dexcom G7 is designed to support the way you manage diabetes, making it simpler, more intuitive and pain-free. Its flexible features make it easy to personalize the experience, so you can get the most out of CGM technology and monitor your glucose levels with greater confidence.
Get a Free Dexcom G7 Trial
Are you living with diabetes and not using CGM? Talk to your doctor about Dexcom G7. We can also help you get started with a free benefits check. Click the button below to send us some basic information.
*If your glucose alerts and readings from Dexcom G7 do not match symptoms or expectations, use a blood glucose meter to make diabetes treatment decisions. †Dexcom G7 can complete warmup within 30 minutes, whereas other CGM brands require up to an hour or longer. ‡Compatible smart devices sold separately: dexcom.com/compatibility. §Individual pricing may vary depending on insurance coverage. IITo learn more about insulin pump integrations and compatibility with Dexcom CGM Systems, visit dexcom.com/integrate. ¶Separate Follow app and internet connection required. #Compatible smartphone is required to pair a new Dexcom G7 sensor with a compatible Apple Watch. To use Share/Follow your compatible Apple Watch must be connected to the internet via Wi-fi. **Patients reported that 94% of Dexcom G7 sensor insertion was painless (mild, no discomfort). ††Compared to prior generation Dexcom CGM system. ‡‡The Dexcom G7 Sensor is waterproof and may be submerged under eight feet of water for up to 24 hours without failure when properly installed.
1 Dexcom, Data on File 2023. 2 Dexcom G7 User Guide. 3 Dexcom, Data on File 2024. 4 dQ&A US Diabetes Connections Patient Panel Report, QI 2023. 5 Seagrove HCP Survey Q2 2022. 6 Freestyle Libre 3 user guide. 7 Freestyle Libre. 3 Plus user guide. 8 Beck RW, et al. JAMA. 9 Beck RW, et al. Ann Intern Med. 10 Martens T, et al. JAMA. Laffel LM, et al. JAMA. 2020;323(23):2388-2396.12 Welsh JB, et al. J Diabetes sci Technol. 2024;18(1):143-7.13 Dexcom, Data on file, 2021.
BRIEF SAFETY STATEMENT: Failure to use the Dexcom Continuous Glucose Monitoring System and its components according to the instructions for use provided with your device and available at https://www.dexcom.com/safety-information and to properly consider all indications, contraindications, warnings, precautions, and cautions in those instructions for use may result in you missing a severe hypoglycemia (low blood glucose) or hyperglycemia (high blood glucose) occurrence and/or making a treatment decision that may result in injury. If your glucose alerts and readings from the Dexcom CGM do not match symptoms, use a blood glucose meter to make diabetes treatment decisions. Seek medical advice and attention when appropriate, including for any medical emergency.
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