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What is Continuous Glucose Monitoring (CGM)?

Continuous Glucose Monitoring (CGM) is a method to track glucose levels throughout the day and night. CGM systems take glucose measurements at regular intervals, up to 24 hours a day, and translate the readings into dynamic data, providing glucose direction and rate of change.


Having this context helps CGM users proactively manage glucose highs and lows, and gives added insight into impacts that meals, exercise and illness may have on an individual’s glucose levels. CGM can also contribute to better diabetes management by helping to minimize the guesswork that comes with making treatment decisions* based solely on a number from a blood glucose meter reading.


Studies have shown that Dexcom CGM systems may help reduce A1C1,2 levels and reduce hypoglycemia, whether users are on insulin injections or pump therapy.3


Traditional Blood Glucose Monitoring (BGM)
vs. Continuous Glucose Monitoring (CGM)


Blood glucose meters display a single glucose value at one point in time with no additional context. CGM systems, by contrast, can provide real-time, dynamic glucose information, showing not only where your glucose is, but where it's heading, and how quickly it's changing.

Traditional blood glucose meter

 If this was your meter reading, what would you do?

Dexcom G6 CGM

Would you respond differently if you knew your glucose was falling rapidly?

(Double arrow down means glucose level is rapidly dropping more than 2.5 mmol/L in the next 15 minutes)

Benefits of Dexcom CGM

Unlike a blood glucose meter (BGM), which provides just a single glucose reading, CGM systems can provide
real-time, dynamic glucose information up to every five minutes. You can gain valuable insight about your glucose levels, rate and direction of change, giving you additional insight to proactively manage your diabetes.

A1C Reduction

Dexcom CGM is proven to lower A1C.1,2 People with Type 1 diabetes experience an average A1C reduction of 1.3%*4

Reduced Hypoglycemia

Numerous studies have shown Dexcom CGM can decrease time spent in
hypoglycemia 1,2,5, and reduce the number of hypoglycemic events5. It helps to know before you’re low!

Active Monitoring, Day and Night

The Dexcom CGM system is equipped with alerts that can warn you of lows and highs, so you can sleep with less worry.

How does CGM work?

CGM users insert a tiny sensor wire just underneath the skin with an applicator. An adhesive patch holds the sensor in place so the sensor can measure glucose levels in the interstitial fluid. A small, reusable transmitter connects to the sensor and sends real-time readings wirelessly to a receiver, so you can view the information.


With the Dexcom G6 CGM System, your current glucose data can be shown on a compatible smart device using the Dexcom G6 App, or on an optional receiver.


To view a list of compatible devices, click here.

What's the difference between Continuous Glucose Monitoring (CGM) and Flash Glucose Monitoring (FGM)?


There are significant differences between the Dexcom G6 CGM System and the Abbott Freestyle Libre Flash Glucose Monitoring System (Freestyle Libre).


Here are a few highlights:



System Name DEXCOM G6 CGM System6 Freestyle Libre7
Indicated for Persons age 2 years and older Adults age 18 years and older who have at least 2 years of experience in
self-managing their diabetes
Sensor Duration 10 days 14 days
Continuous Data Visibility


No unless you scan

Can you make treatment decisions without fingerstick confirmation?

Yes, except fingerstick is required:

  • When symptoms do not match sensor readings
  • When G6 doesn't show a number, arrow, or both

Yes, except fingerstick is required:

  • During times of rapidly changing glucose levels
  • To confirm hypoglycemia 
  • To confirm impending hypoglycemia
  • When symptoms do not match sensor readings
Real-time Low/High BG Alerts


No, unless you scan

Urgent Low Soon Alert



Continuous remote monitoring by family or caregiver

Yes, by using the Follow App on a smart device§ (Internet connection required)

Shared readings occur when the user physically scans using Freestyle LibreLink on a smartphone8 and the followers use the LibreLinkUp app


Who should use CGM?

People living with diabetes on intensive insulin therapy could benefit from CGM, as it offers real-time glucose levels at a glance, trending data and alerts to help users proactively manage their diabetes.


To assist both individuals with diabetes and healthcare professionals to better understand whether real-time CGM is an appropriate option for their diabetes management, an article in the Journal of the Endocrine Society9 published the following considerations:



  • Patient is 2 years of age or older
  • Currently treated by intensive insulin therapy  
  • Experiencing frequent hypoglycemia
  • Hypoglycemia unawareness
  • Excessive glucose variability
  • Varying and/or intensive activity
  • Desire to improve glycemic control
  • Understands behaviors that influence glycemic control
  • Willing and able to use real-time CGM on a nearly daily basis
  • Willing and able to learn how to use device

Is the Dexcom G6 CGM System right for me?

Learn more about Dexcom G6, its features, what makes it different from the previous generation of CGM technology, how much it costs and how you can get it.

*If your glucose alerts and readings from the G6 do not match symptoms or expectations, use a blood glucose meter to make diabetes treatment decisions.

† for patients with baseline A1C =8.5%

‡ Requires the Follow App and an internet connection. Followers should always confirm readings on the Dexcom G6 CGM App or Receiver before making treatment decisions.

§ Click here for a list of compatible devices.

1. Beck RW, Riddlesworth T, Ruedy K, et al. Effect of continuous glucose monitoring on glycemic control in adults with type 1 diabetes using insulin injections: The DIAMOND randomized clinical trial. JAMA. 2017;317(4):371-378.

2. Lind M, Polonsky W, Hirsch IB, et al. Continuous glucose monitoring vs conventional therapy for glycemic control in adults with type 1 diabetes treated with multiple daily insulin injections: The GOLD randomized clinical trial. JAMA. 2017;317(4):379-387.

3. Beck RW, Riddlesworth TD, Ruedy KJ, et al. Effect of initiating use of an insulin pump in adults with type 1 diabetes using multiple daily insulin injections and continuous glucose monitoring (DIAMOND): a multicentre, randomised controlled trial. Lancet Diabetes Endocrinol. 2017;5(9):700-708.

4. Billings LK, Parkin CG, Price D. Baseline Glycated Hemoglobin Values Predict the Magnitude of Glycemic Improvement in Patients with Type 1 and Type 2 Diabetes: Subgroup Analyses from the DIAMOND Study Program. Diabetes Technol Ther. 2018;20(8):561-565.

5. Heinemann L, Freckmann G, Ehrmann D, et al. Real-time continuous glucose monitoring in adults with type 1 diabetes and impaired hypoglycaemia awareness or severe hypoglycaemia treated with multiple daily insulin injections (HypoDE): a multicentre, randomised controlled trial. Lancet. 2018;391(10128):1367-1377.

6. Using Your G6 Dexcom Guide

7. Freestyle Libre User Guide

8. Freestyle Librelink Smartphone Compatibility Guide

9. Aleppo G. Laffel L. et al. A Practical Approach to Using Trend Arrows on the Dexcom G5 CGM System for the Management of Adults with Diabetes Journal of the Endocrine Society. December 2017 Vol 1 Iss.12.