Dexcom introduces its first over-the-counter continuous glucose monitor. Here's what it's like.

• Dexcom launched its first over-the-counter continuous glucose monitor called Stelo on Monday.
• An individual can purchase a one-month supply of Stelo online for $99 or opt for a monthly subscription at $89. Additionally, Stelo is eligible for FSA and HSA.
• The primary target audience for Stelo is the 125 million Americans who do not use insulin and have prediabetes or Type 2 diabetes.
• Since early August, CNBC has been testing Stelo, a device that enables patients to understand the impact of diet, exercise, stress, and other elements on their glucose levels.

The continuous glucose monitor Stelo, announced by on Monday, is now available for purchase in the U.S.

CGMs are small sensors that measure glucose levels in real time and are typically prescribed to patients with diabetes to alert users, their loved ones, and their doctors to emergencies. Glucose is a type of sugar people receive from food and is the body's main source of energy.

Stelo is designed for individuals with prediabetes or Type 2 diabetes who do not require insulin, but it is also accessible to those without these conditions. A one-month supply can be purchased online for $99, or individuals can opt for a monthly subscription at $89.

Stelo can be paid for using Flexible Spending Accounts and Health Savings Accounts, as stated by Dexcom.

Dexcom's Stelo is the first product that does not require a prescription and is accessible to millions of Type 2 patients who have been unable to get prescriptions or coverage for continuous glucose monitors. This marks the company's official entry into the prediabetes market.

Dexcom announced that over 125 million Americans with prediabetes or Type 2 diabetes are not utilizing insulin, prompting the company to develop Stelo to educate this patient group on maintaining healthy glucose levels.

"Jake Leach, chief operating officer at Dexcom, stated in an interview with CNBC that the goal is to assist individuals in understanding the effects of dietary choices and habits on glucose levels over time. This involves discovering new information and utilizing it to develop healthier habits."

How it works

In March, the U.S. Food and Drug Administration approved Stelo, the first over-the-counter continuous glucose monitor to be cleared for use. However, Dexcom's competitor received clearance for two similar devices in June.

Dexcom is collaborating with to deliver Stelo, and users with a subscription can opt to skip or adjust their delivery date, which is usually scheduled at a 30-day interval from the initial sign-up.

The stelo, a gray, quarter-sized, half-inch thick device, is worn on the upper arm and lasts for 15 days before needing replacement.

The Dexcom sensor wirelessly transmits data to a smartphone app, allowing users to select their glucose level target range based on their medical history. The target range is based on established medical standards, with most people falling between 70 and 180 mg/dL, according to the American Diabetes Association.

Upon opening the Stelo homepage, users will view their most recent reading, which is updated every 15 minutes. Additionally, they will see a graph displaying their daily readings, featuring a shaded green area to represent the target range. As they scroll down, they will find a summary of the amount of time spent within the target range over time.

Stelo notifies users of substantial glucose spikes, which occur when bloodstream sugar levels rapidly increase and decrease, typically after eating.

To prevent serious health problems like diabetes, heart disease, and kidney disease in the long term, the Centers for Disease Control and Prevention advise keeping glucose levels within Stelo's target range. Dexcom encourages users to do the same.

The "Events" page on the Stelo app is where users can log meals, activity, fingersticks, or other notes. Leach emphasized the importance of logging an entry when experiencing a significant spike to reflect on potential causes.

Stelo alerts users about significant spikes in their levels, rather than every minor increase. Leach explained that this is a deliberate design decision aimed at highlighting the more substantial fluctuations that patients experience.

He stated that even for someone with normal glucose and occasional spikes, the app would focus on identifying the most significant spikes and then prompt the user with the question, "What happened there?"

For users who want to learn more about glucose and its causes, the app's "Learn" tab offers a wealth of educational materials. The articles are concise, typically just a few sentences long, and are organized into categories such as "Stelo Basics," "Glucose Deep Dive," "Nutrition," "Exercise," "Sleep," and "Stress."

CNBC Tests Stelo

Since early August, I have been using Stelo and overall, I find it user-friendly and beneficial.

Upon receiving my monitors, I immediately applied the sensor to my arm and paired it with the Stelo app. The process was simple and intuitive, with the app providing clear, step-by-step instructions.

I quickly and painlessly attached a Dexcom CGM sensor to the back of my right arm by following these steps: cleaning the area, placing the applicator, pressing the button, and popping the sensor into place.

After connecting to the Stelo app via Bluetooth, the monitor requires around 30 minutes to warm up.

I encountered some problems with my CGM sensor. After my device warmed up, I received an error message stating "Brief Sensor Issue." The message instructed me not to remove the sensor, but to wait for the issue to resolve. Despite this, I noticed light bleeding by evening, so I decided to remove the sensor.

I applied a second CGM to my other arm, and it functioned properly. I have been using it consistently without any issues with bleeding. Leach stated that if users encounter difficulties with the product, they can contact the chat interface on Stelo's website for a replacement or to have their questions answered.

After successfully setting up my second sensor, the rest of the process went smoothly.

The Stelo app is user-friendly and straightforward, with simple meal and exercise logging features. Users can also import their sleep and activity data from Apple Health or Android's Health Connect, making it a convenient option.

If you're new to using a CGM, I suggest reading the articles in the "Learn" tab to gain a better understanding of glucose, its effects, and why it's important. Dexcom does an excellent job of explaining these concepts in simple language.

As I wear the sensor for longer periods, I can better sense that the algorithm is adapting to my habits and preferences. While I don't receive notifications every time my glucose levels rise, the app alerts me when there's a significant spike. Additionally, the app is starting to recognize my patterns. For example, it recently informed me that my glucose levels typically increase between 5 p.m. and 7 p.m., which is usually around the time I eat dinner.

I often forget that I'm wearing a waterproof sensor, which is easy to wear under various types of clothing and jackets. However, I need to be careful when pulling on long sleeves, as the sensor can snag a bit.

Stelo has been a valuable tool for me in understanding how my body responds to different foods. By making small adjustments, such as eating carbs last, I was able to reduce spikes. CGMs provide a valuable window into the body, and Stelo is an easy-to-use option for those looking to understand their glucose data.