Using Your Dexcom CGM System

Setting Up Sharing and Dexcom Clarity

What is Dexcom Clarity?

Dexcom Clarity is an important part of your CGM system, providing a holistic view of your diabetes management by highlighting glucose patterns, trends, and statistics.
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How do I get to Dexcom Clarity?

Go to from an internet browser with internet connection. Review Clarity's list of computer and internet requirements if needed.

Compatible Software and Apps

What if my smartphone is NOT compatible with Dexcom ONE?

Before upgrading your smart device or its operating system, check If your device is not compatible, you may not be able to download the Dexcom ONE app, or it may not work properly.

Is my smartphone compatible with the Dexcom ONE app?

A variety of iOS and Android smartphones are compatible with the Dexcom ONE app. To view a list of compatible smartphones, visit

System Overview

What are the Dexcom ONE system components?

The Dexcom ONE CGM system requires, Dexcom ONE sensors, Dexcom ONE transmitters and a compatible smart device*

Using the Dexcom CGM App

How do I set up and use Dexcom ONE alerts?

Dexcom ONE gives you the option of turning on alerts when you set up your system. You just follow the prompts on your screen. If you want to turn on or change your alerts after setup, go to Settings > Alerts.

How do I set up my Dexcom ONE app?

Set up your Dexcom ONE app before inserting your sensor

How do I find my sensor readings and glucose trend screen in my app?

Dexcom ONE sensor glucose readings and trend graph appear on your app home screen and on your receiver home screen.

Inserting and Starting Your Sensor and Transmitter

How do I replace my sensor and start a new sensor session?

There are two ways to end your sensor session and start a new one.

What is a sensor code and why do I need one?

A sensor code allows you to use the Dexcom ONE CGM System without the need for fingersticks or calibrations. When you start a new sensor, you must enter a code into your display device, either manually or by taking a photo, as each sensor has its own code printed on the back of the adhesive patch. Do not use a code from a different sensor or make up a code. If you do, your sensor will not work as well and could display inaccurate data.

How do I insert my Dexcom ONE sensor?

Dexcom designed the Dexcom ONE CGM system sensor auto-applicator for easier, more consistent sensor insertions. We recommend viewing the following video for a helpful demonstration of the sensor insertion and transmitter attachment process.

Is it painful to insert a Dexcom ONE sensor?

The Dexcom auto applicator was designed for easier, more consistent sensor insertions. According to a survey of Dexcom users, 84% reported that the initial sensor insertion was painless, and 100% reported that the applicator was easy to use.

CGM and Daily Life

Can I shower or swim while wearing my Dexcom ONE?

Once snapped into place, the transmitter is water resistant. Swim, shower, take a bath: no need to worry about water and your Dexcom ONE, just leave your display device in a dry area.

How do I use Dexcom ONE to make treatment decisions?

With Dexcom ONE, you can make treatment decisions without using your blood glucose (BG) meter.

What is Continuous Glucose Monitoring (CGM)?

Dexcom Continuous Glucose Monitoring (CGM) tracks glucose levels throughout the day and night and can alert you if your levels go too high or low.

Setting Up Your Smartphone or Receiver

Are there any iPhone/iOS settings I should or shouldn't use with my Dexcom ONE app?

Here are some recommended settings for iPhone devices, to help ensure you get all Dexcom ONE app alerts and sensor readings.

Are there any Android/OS settings I should or shouldn't use with my Dexcom ONE app?

Here are some recommended settings for Android devices, to help ensure you get all Dexcom ONE app alerts and sensor readings. Visit for a list of devices and operating systems compatible with the Dexcom ONE app.

Using Your Sensor and Transmitter

My 10-day sensor session is going to end soon, and I want to change my sensor early. Can I change the sensor now?

Yes, you can change a Dexcom ONE sensor before the session ends.

How do I keep my sensor on for the full 10-day wear?

Dexcom sensors are manufactured with a special adhesive to help them stick to your skin after sensor insertion.

What do I do if my Dexcom ONE applicator won't come off?

If the Dexcom ONE applicator gets stuck, don't panic. Simply remove the applicator and sensor following these instructions...

How do I replace my transmitter?

You will get a notification when a Dexcom ONE transmitter battery has died or the system detects a problem.

Sensor Adhesion Issues

How to avoid irritated/sensitive skin from sensor adhesive?

If you have irritated or sensitive skin please work with your healthcare professional (HCP).

How can I avoid irritated or sensitive skin caused by the sensor adhesive?

These considerations, skin barriers, and professional tips may help. Remember, what works best for one person may not work best for everyone.

How do I properly remove the sensor adhesive?

This is a summary of a clinical article published by clinicians independent from Dexcom, based on their knowledge and experience.* Dexcom has not tested these approaches, nor do we endorse these specific approaches.

Troubleshooting (Using Your Dexcom CGM)

What does the Signal Loss alert mean?

The Signal Loss alert tells you when you're not getting Dexcom ONE readings. Your display device may be too far from your transmitter or there may be something, such as a wall or water, between your transmitter and your display device.

Why can't I hear my Dexcom ONE alerts?

Check the following if you can't hear your Dexcom ONE alerts...

What are the best practices to minimize signal loss on my phone?

Review the following information to make sure that you continue to receive CGM values when using a compatible smart device...

What should I do if my sensor reading and blood glucose value don't match?

There may be times when your readings temporarily don't match, but don't panic--they are likely to become closer over time. You may find that this occurs for a few common reasons...

Smartphone Compatibility

I want to get a new phone. Will this affect my Dexcom ONE?

A variety of iOS and Android smartphones are compatible with the Dexcom ONE app. To view a list of compatible smartphones, visit

Common Dexcom CGM Questions

Can Dexcom sensors be calibrated?

All Dexcom products can be calibrated, but not required. All our systems are designed to work properly without calibrations. Calibration is therefore an optional function.

How accurate is my Dexcom ONE compared to my blood glucose meter?

Dexcom CGM systems provide much more information for users than traditional Self-Monitoring of Blood Glucose (SMBG) does.

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