Continuous glucose monitors: What are they and how can they help better manage diabetes?

A young woman using a continuous glucose meter checks her blood sugar on an app.

If you’re one of the more than 37 million people in the U.S. who’s been diagnosed with diabetes, one of the most important aspects of managing your condition is monitoring your blood sugar.1

Uncontrolled blood sugar can permanently damage your eyes, nerves, kidneys, and blood vessels, raising the risk of heart attack, stroke, kidney failure, and other complications. By tracking blood sugar, you’re better able to figure out how much insulin your body needs and when.

Ways to monitor blood sugar

Until fairly recently, the best way to do this was through finger-prick blood tests. You place a test strip inside a glucose meter and prick your fingertip with a lancet to get a small blood sample.

Blood glucose meters are accurate but they measure blood sugar at one specific moment in time, so you need to repeat the process multiple times a day.

In 1999, the U.S. Food and Drug Administration approved the first continuous glucose monitor (CGM) to simplify the monitoring process. Here’s what you should know about CGMs and how they can help more easily manage diabetes.

What is a continuous glucose monitor and how does it work?

A continuous glucose monitor (CGM) is a wearable device that continuously tracks blood sugar levels.

  • It uses a small sensor that’s placed just under the skin of the abdomen or arm that measures blood sugar (glucose) levels in fluid under the skin, 24 hours a day.
  • The device provides readings every 5 minutes and that data is transmitted wirelessly to a handheld device, app on your phone, or an insulin pump.
  • You can wear a CGM all the time, including the gym, shower, and pool, and you can review the data anytime you want.

What are the benefits of continuous glucose monitors?

There are several benefits to using a continuous glucose monitor (CGM):

  • Access to real-time data. CGMs allow you and your doctor to respond to data in real time and make changes to your care plan.
  • Fewer complications. CGMs alert you to highs and lows in blood sugar so that you can make quick decisions to prevent complications. These alerts make it easier to manage diabetes, target the appropriate insulin dose, and keep your blood sugar in the target range. Patients who use CGMs are less likely to experience hypoglycemia and hyperglycemia and have a lower average A1C.
  • Shows you the big picture. Continuous glucose monitors provide a more complete view of how your blood sugar changes over time and give you a better understanding about how food, physical activity, stress, medications, and illnesses affect your blood sugar levels. You and your doctor can review the data for patterns and trends, allowing you to receive more personalized care.
  • You can automate your insulin. Insulin pumps can work with your CGM to automatically adjust your insulin levels based on the data from your device.
  • Fewer finger pricks. Although a CGM doesn’t completely eliminate the need for finger pricks, it does reduce the frequency of them.

What are some drawbacks of continuous glucose monitors?

While there are many benefits to wearing a continuous glucose monitor (CGM), there are also some drawbacks.

  • They can be expensive. One of the most common drawbacks is cost, especially if you don’t have health insurance. The average starter kit with replaceable sensors can range anywhere from one thousand to several thousand dollars. That number varies based on the brand and the individual components like sensors and transmitters that need to be replaced regularly. Some health plans cover the cost of all or some of the CGM system. In most cases, you can use funds from a healthcare spending account (like an HSA, FSA, or HRA) to help offset the cost.
  • They aren’t perfect. While CGMs monitor blood glucose continuously, readings are delayed by about 10 to 15 minutes. That means that there are instances where your CGM may show a stable reading, despite you feeling like something is “off.” In those scenarios, you’ll need to use a finger-prick test as a backup to confirm your CGM results and provide insight into why your reading isn’t matching how you feel.
  • There is a learning curve. CGMs can be complicated and hard to use initially. You can work with your pharmacist or healthcare provider on how to use the device.
  • They can be uncomfortable. Some people experience redness, swelling, and blistering at the administration site.

We’re here to help

At Express Scripts® Pharmacy, you have 24/7 access to pharmacists who have special training and knowledge around diabetes, including medications, blood sugar monitoring, and other ways to help you manage your condition. Our pharmacists can answer all your diabetes related questions and provide guidance on CGM devices. They can also check your benefits to see what products are covered by your health plan.

If your health benefits include home delivery through Express Scripts® Pharmacy, you can get your diabetes supplies, including CGMs, delivered right to your door with free shipping.

Depending on your plan, you may also be eligible for remote diabetes monitoring, coaching, and counseling.

1 Centers for Disease Control and Prevention: Diabetes Fast Facts (accessed July 27, 2023):

Posted date: October 20, 2023

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