Continuous Glucose Monitors (CGMs): What They Are and Why They Matter

Managing blood sugar is at the heart of diabetes care, and for decades, fingerstick glucose checks were the only way to track levels. Today, continuous glucose monitors (CGMs) have transformed the way patients and providers understand blood sugar patterns. Whether you are living with diabetes or monitoring early changes in your blood sugar, CGMs can provide powerful insight into your health.

What is a Continuous Glucose Monitor (CGM) and How Does It Work?

A continuous glucose monitor is a small device worn on the skin that measures glucose in the fluid just beneath the skin (interstitial fluid). Instead of checking a single number a few times per day with fingersticks, CGMs record readings every few minutes—day and night—creating a detailed picture of how food, activity, stress, and medications affect blood sugar.

Most systems include:

• A small sensor placed under the skin (usually on the arm or abdomen)

• A transmitter that sends glucose data wirelessly

• A smartphone app or reader where patients can view real-time results, trends, and alerts

  
  

Original Indications for CGMs

CGMs were first developed for patients using insulin therapy—particularly those with type 1 diabetes or insulin-dependent type 2 diabetes. For these patients, avoiding hypoglycemia (dangerously low blood sugar) and managing post-meal spikes is critical, and CGMs offer life-saving alerts and insights that fingersticks cannot provide. Insurance coverage for CGMs has historically focused on these patients, making access more straightforward for those on multiple daily insulin injections or insulin pumps.

Expanding Use: Non-Insulin Diabetes and Pre-Diabetes

Over the past several years, the usefulness of CGMs has expanded beyond insulin users. Many people with type 2 diabetes who are not on insulin, and even individuals with pre-diabetes, are now exploring CGMs as a tool for:

• Understanding how different foods impact blood sugar

• Identifying patterns of post-meal spikes or nighttime elevations

• Supporting lifestyle changes, such as diet and exercise

• Increasing accountability and motivation through real-time feedback

  
  

Real-Life Example

For instance, Myrna, a 52-year-old with pre-diabetes, began using an OTC CGM to better understand how her meals affected her blood sugar. She noticed that even modest portions of pasta caused spikes, while walking for 15 minutes after meals kept her glucose in a healthy range. Using this real-time feedback, Myrna adjusted her meals and incorporated daily walks, which helped her improve her glucose patterns and prevent progression to type 2 diabetes.

With the release of over-the-counter (OTC) CGMs, access has widened. These devices can be purchased without a prescription, giving more people the opportunity to see how their choices influence blood sugar in real time.

Available OTC CGMs

As of 2025, two major OTC CGMs have been approved for use in the United States:

1. Dexcom Stelo

• Manufacturer: Dexcom

• Intended Users: Adults aged 18+ who do not use insulin, including those with type 2 diabetes or pre-diabetes.

• Features: Measures, records, analyzes, and displays glucose values in real time.

• Availability: Online through Dexcom and authorized retailers such as Amazon.

• Pricing: One-time purchase: $99 for a 2-sensor pack (up to 30 days of wear). 

Monthly subscription: $89 per month for a 2-sensor pack. 

• Note: Not designed for patients at risk of severe hypoglycemia.

2. Abbott Lingo

• Manufacturer: Abbott

• Intended Users: Adults aged 18+ who do not use insulin, including those with type 2 diabetes or pre-diabetes.

• Features: Adhesive skin patch with smartphone app for continuous readings.

• Availability: Online through Abbott and authorized retailers such as Amazon.

• Pricing: $49 for 2 weeks, $89 for 4 weeks, or $249 for 12 weeks of usage.

How to Obtain a CGM

• Insulin-dependent diabetes: Prescription required; insurance often covers most costs.

• Non-insulin diabetes or pre-diabetes: Prescription may be obtained but coverage varies; OTC options are available for direct purchase.

Cost and Insurance Coverage

• With insurance: Typically covers patients on insulin.

• Without insurance or for non-insulin users: Out-of-pocket costs range from ~$70–$200/month depending on device and plan.

Takeaway

CGMs are no longer just for people on insulin—they are powerful tools for anyone looking to better understand and manage their blood sugar. Whether you’re living with diabetes or taking steps to prevent it, CGMs can provide real-time insight to guide healthier choices.

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At Cardona Direct Primary Care, Dr. Cardona and Dr. Garland provide personalized healthcare, including direct primary care, obesity medicine, and aesthetic treatments. Dr. Cardona is board-certified in both family medicine and obesity medicine and has a special interest in medical weight loss. Dr. Garland is board-certified in family medicine and is a certified medical marijuana provider. She has a special interest in skincare and is eager to assist with your individual skincare needs. Located in Jacksonville, FL, we are dedicated to prioritizing you. Contact us at 904-551-4625 or visit our website for more information.