Whether you are new to continuous glucose monitoring (CGM) or a seasoned pro, one thing remains true: proper skin preparation is crucial for ensuring your sensor stays put and functions as intended. In this guide, I will walk you through the best practices for preparing your skin before applying the Dexcom G7 or FreeStyle Libre 2 sensor. Preparing your skin properly helps:
- Improve adhesion (sensor stays on longer)
- Prevent skin irritation
- Reduce sensor errors
- Maximize comfort during wear
- Avoid premature sensor failure
Step-by-Step Skin Preparation Guide
1. Choose the Right Sensor Site
For both sensors, the back of the upper arm is the manufacturer approved location. Avoid areas that:
- Have scars, moles, or tattoos
- Are overly hairy
- Have lots of movement or pressure (like where you sleep)
- Are prone to sweating or rubbing from clothing
2. Wash Your Hands
Before you even touch the sensor or your skin, wash your hands with soap and water. Dry thoroughly. Avoid using hand sanitizer as it can leave a residue that interferes with the adhesive.
3. Clean the Skin
Use an alcohol wipe to clean the area where you’ll apply the sensor. Rub firmly to remove oils, lotions, sunscreen or any dirt or debris.
Let the alcohol dry completely. Don’t rush this step as moisture under the sensor can affect the stickiness.
4. Trim Excess Hair
If the site is hairy, use small scissors or electric clippers to trim the hair. This allows the adhesive to stick better and reduces discomfort during removal. Avoid shaving with a razor, as it can cause micro-cuts and irritation.
5. Apply a Skin Barrier Wipe (Optional)
For sensitive skin or extra adhesion, you can apply a barrier wipe like SKIN TAC. It is an adhesive enhancer and SKIN TAC is used to make adhesives stick better to your skin for longer. Let it dry completely before applying the sensor.
Quick tip: Avoid putting barrier wipes directly where the sensor needle will go, instead apply around the insertion site.
6. Let Everything Dry
This is critical. Damp skin reduces adhesion and increases the chance of skin irritation or sensor dislodgement.
7. Apply the Sensor
Apply the sensor as instructed by the app or dedicated reader.
Read my article on:
These posts will provide a more detailed guide on how to apply your sensor. Once the sensor is applied press down and rub around the adhesive for 10–20 seconds to activate the glue.
8. Add an Overpatch (if needed)
For those that sweat a lot, live in a humid climate, or physically active then consider using an overpatch or tape to further secure your sensor.
The overpatch is meant to improve adhesion, improve water-resistance and protect against snags. Some users apply an overpatch as soon as they place a new sensor, while others wait several days or apply it only when they notice the original adhesive starting to lift. Options include TEGADERM or KT Tape among many others on the market.
TEGADERM is a transparent medical dressing designed by 3M for protecting wounds, catheter sites, and medical devices while allowing visibility and breathability. TEGADERM works great as an overpatch for CGMs like Dexcom G7 and Freestyle Libre 2 sensors.
Interestingly, the Dexcom G7 comes with an overpatch that can help further secure the sensor for the 10-day wear time.
9. Avoid Water or Sweat for a Few Hours
Allow at least 1 to 2 hours before showering, swimming or exercising heavily to allow the adhesive time to bond fully with your skin.
Final Thoughts
Proper skin prep might take a few extra minutes, but it can save you from frustration later. Whether you are using the Dexcom G7 or the FreeStyle Libre 2, this routine helps ensure reliable sensor wear and optimal performance.
If you’ve struggled with sensors falling off, causing irritation, or not lasting the full wear period try implementing this prep routine and see the difference.
Bonus Advice
Once your sensor has reached the end of its wear time, here are some tips to help you get the sensor off easily and painlessly.
Typically, after the full wear time, the sensor should be easy to remove, however sometimes you may need to help finesse it off. Using some baby oil may help the sensor release from your skin.
Afterwards, using a product like REMOVE made by smith&nephew can help clean up any leftover adhesive material left by the sensor. Ideally, alternating sites between sensors could help give a break for the area, but using REMOVE would help prep the area if you are not able to alternate sites.
REMOVE works by gently dissolving and loosening adhesive residue left behind by medical tapes, dressings, or devices like CGMs, insulin pumps, ostomy appliances, etc. These wipes contain a non-irritating, skin-safe solvent that breaks down the adhesive bonds as well as aloe to help condition and soothe the skin.