How to Put on a Dexcom G7

By Web Admin
Medical Disclaimer

This article is for informational purposes only and does not constitute medical advice. Always consult your physician or a qualified healthcare provider regarding any medical condition or treatment.

Key Takeaways

  • The Dexcom G7 sensor goes on the back of the upper arm for adults, abdomen for adults and pregnant users, or upper buttocks for ages 2 to 6 — choose a flat fleshy area at least 3 inches from the last sensor site.
  • Clean the skin with soap and water, dry completely, and avoid lotions, creams, and antibacterial wipes other than the included alcohol pad — residue prevents proper adhesion.
  • Hold the applicator firmly against the skin, press the button until you hear a click, hold 5 seconds, then lift away — total time about 30 seconds, with no manual needle to handle.
  • The 30-minute warm-up period after application is normal — readings appear in the Dexcom app once the sensor finishes calibrating.
  • Common mistakes include touching the adhesive face, applying to recent injection sites, choosing a hairy or muscular area, and rushing the press-and-click step.
Table of Contents
  1. What You Need
  2. Choose the Right Site
  3. Site Preparation
  4. Apply the Sensor
  5. Pair the Sensor
  6. Common Application Mistakes
  7. Improving Adhesion
  8. Wear-Time and Replacement
  9. Removing a Sensor
  10. Skin Reactions and What to Do
  11. When to Replace Early
  12. Related Reading
  13. The Bottom Line

To put on a Dexcom G7, choose the back of the upper arm (adults) or abdomen, clean the skin with soap and water and dry completely, peel off the adhesive backing, press the applicator firmly against the skin, push the orange button until you hear a click, hold 5 seconds, and lift away. Total application time is about 30 seconds. The sensor warms up for 30 minutes before showing readings in the Dexcom G7 app.

What You Need

  • Dexcom G7 sensor box (each contains the applicator and adhesive sensor preloaded)
  • Soap and water for site cleaning
  • Optional: alcohol pad (some kits include one)
  • Optional: Skin Tac or barrier wipe for sensitive skin
  • Optional: trimmer or razor if the area is hairy
  • Smartphone with the Dexcom G7 app installed and Bluetooth enabled

Choose the Right Site

User Approved Sites
Adults (18+) Back of upper arm; abdomen
Pregnant adults Abdomen; upper buttocks
Children ages 7 to 17 Back of upper arm; abdomen
Children ages 2 to 6 Upper buttocks only

Site Selection Tips

  • Flat fleshy area without obvious bone or muscle directly underneath
  • At least 3 inches away from your last sensor site
  • Away from beltlines, waistbands, or other clothing pressure points
  • Away from scars, tattoos, stretch marks, or moles
  • Not on a recent injection or insulin pump site
  • Skin that you can keep clean and dry

Site Preparation

  1. Wash the area with soap and water
  2. Pat or air dry completely — do not skip this step
  3. If hairy, trim short with clippers (do not shave to bare skin)
  4. Optional: clean with the included alcohol pad and let air dry fully
  5. Optional: apply a thin layer of Skin Tac or skin barrier wipe and let dry
  6. Do not apply lotion, cream, oil, or moisturizer to the site that day

Apply the Sensor

  1. Open the sensor box and remove the applicator
  2. Twist off the cap (do not touch the adhesive face after this point)
  3. Position the applicator flat against the prepared skin
  4. Hold steady — applicator must be perpendicular to the skin
  5. Press the orange button firmly with your thumb until you hear a click
  6. Hold the applicator in place for 5 seconds
  7. Lift straight away — the sensor and adhesive remain on the skin
  8. Run a finger around the edge of the adhesive patch to confirm secure contact
  9. Discard the used applicator in a sharps container

Pair the Sensor

  1. Open the Dexcom G7 app on your phone
  2. Select “Start New Sensor”
  3. Scan the QR code on the applicator or enter the sensor code
  4. Confirm pairing — the app should show a “Sensor Warming Up” screen with a 30-minute countdown
  5. Optionally pair to your Apple Watch or compatible insulin pump
  6. After 30 minutes, glucose readings appear and update every 5 minutes

Common Application Mistakes

  • Touching the adhesive face — leaves skin oils that prevent stick
  • Applying over hair without trimming first
  • Applying to skin that is still wet or recently moisturized
  • Pressing the button at an angle rather than perpendicular
  • Lifting the applicator before the click registers
  • Choosing a site that flexes a lot (joint adjacent areas)
  • Reusing the same exact site as the previous sensor

Improving Adhesion

  • Skin Tac wipe before application
  • Tegaderm or Hypafix over-patch on top after application
  • Dexcom-specific overlay patches (sold by Dexcom and third parties)
  • Moisture-wicking armband during heavy sweat or swim
  • Avoid hot tubs and saunas
  • Skip oil-based sunscreens and lotions on the site during wear
  • Pat dry rather than rubbing after showers

Wear-Time and Replacement

  • Sensor wears for 10 days plus a 12-hour grace period after expiration
  • App reminds you 6 hours before expiration
  • Apply the next sensor anywhere on an approved site at least 3 inches from the current location
  • If the current sensor fails or falls off early, contact Dexcom for a replacement

Removing a Sensor

  1. Use mineral oil or unisolve adhesive remover around the edges
  2. Gently lift one corner and slowly peel
  3. If skin is very irritated, soak in warm water first
  4. Wash the area afterward with soap and water
  5. Apply moisturizer and wait at least one cycle before applying a new sensor in the same exact spot

Skin Reactions and What to Do

  • Mild redness usually resolves over a day or two
  • Persistent rash may be from adhesive — try a barrier wipe (Cavilon, Skin Prep) before next application
  • Severe itching, weeping, or bleeding warrants stopping and consulting your prescriber
  • Some users develop allergy to acrylates over months — alternative options include using an over-patch or switching CGMs

When to Replace Early

  • Sensor falls off completely
  • Adhesive lifts more than 50 percent
  • Readings are persistently inaccurate compared to fingersticks
  • Sensor displays a “fail” or “replace” alert in the app
  • Localized pain, redness, or warmth around the site

For more on Dexcom G7 and other CGM options, see our guides on detection of prediabetes and treatment options.

The Bottom Line

To put on a Dexcom G7: choose the back of the upper arm or abdomen (or upper buttocks for young children), wash and dry the site, hold the applicator perpendicular and flat against the skin, press the orange button until you hear a click, hold 5 seconds, and lift away. Pair via the Dexcom G7 app and wait through the 30-minute warm-up before readings appear. Skin Tac and over-patches help adhesion in active or sweaty users. Avoid the same exact spot two cycles in a row, and never apply over recent injection sites or scars. The sensor wears for 10 days plus a 12-hour grace period.

Frequently Asked Questions

Where do you put a Dexcom G7?

For adults, the FDA-approved sites are the back of the upper arm and the abdomen. For pregnant users, the abdomen and upper buttocks are options. For children ages 2 to 6, the upper buttocks is the only approved site. Choose a flat, fleshy area with no recent injection sites, scars, tattoos, or stretch marks.

How do you start a new Dexcom G7 sensor?

Remove the old sensor, prepare the new site (wash with soap and water, dry completely, optionally use the included alcohol pad and let dry), open the new sensor packaging, peel off the white adhesive backing, hold the applicator flat against the skin, press the orange button until you hear a click, hold 5 seconds, then lift the applicator away. Pair via the Dexcom G7 app.

Why won't my Dexcom G7 sensor stick?

Common causes are skin oils or lotions on the application site, hair under the adhesive, sweat or moisture during application, or the wrong site choice (very muscular or thin areas). Cleaning with soap and water then alcohol, drying completely, shaving the site if hairy, and using an over-patch or skin-prep wipe (like Skin Tac) can help.

How long does Dexcom G7 take to start reading?

After application, the G7 has a 30-minute warm-up period before showing glucose readings. The Dexcom app displays a countdown. During warm-up the sensor is calibrating to your interstitial fluid; readings before completion are not provided. Once warm-up ends, readings update every 5 minutes for 10 days.

Sources

  1. Dexcom. Dexcom G7 User Guide and Quick Start Guide.
  2. Dexcom. Sensor Wear and Site Selection Recommendations.
  3. U.S. Food and Drug Administration. Dexcom G7 Approval and Labeling.
  4. American Diabetes Association. Standards of Care in Diabetes 2024.

Related Articles

man in white long sleeve shirt holding black dslr camera

H Pylori Test and Diabetes

H pylori testing for adults with diabetes — bacterial stomach infection with possible diabetes link, testing methods (breath, stool, blood, endoscopy).