A tiny sensor with a very demanding job
A CGM has to survive a lot. It gets dressed over, slept on, showered with and occasionally caught on a door frame that definitely was not there a moment ago.
Add summer heat, exercise, body lotion or a day in the pool and even good adhesive can have a difficult time. A sensor beginning to lift early is frustrating—not only because the device is expensive and important, but because constantly checking the edges can make it hard to forget about diabetes for five minutes.
There is no method that guarantees perfect adhesion for every person. Skin, climate, sensor site and activity all make a difference. However, careful preparation gives the adhesive its best chance.
Start with completely clean, dry skin
Dexcom’s UK guidance recommends removing residue left by a previous sensor, then cleaning and drying the new site twice: first with soap and water, followed by a thorough alcohol wipe, allowing the skin to dry fully after each step.
That final word—fully—is important. Applying a sensor while alcohol, water or sweat remains on the skin can stop the adhesive forming a good bond.
Most other CGM suppliers advise the same.
Before application, I avoid putting these products on or close to the chosen site:
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Body lotion
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Oil
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Fake tan
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Sunscreen
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Perfume or body spray
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Creamy or moisturising shower products that leave a residue
If I have just exercised, showered or been out in hot weather, I wait until my skin is cool and completely dry.
Think about friction before choosing the site
An approved site can still be inconvenient if it sits beneath a bra strap, waistband, tight sleeve or the edge of a bag.
Before inserting a sensor, I think about the next several days rather than only that moment. Will clothing repeatedly rub it? Am I likely to sleep on it? Will a car seatbelt or handbag strap pass over it? Could it catch while I am getting dressed?
I always follow the approved placement guidance for my specific Dexcom model and age group. Within those options, rotating sites helps give the skin time to recover and avoids repeatedly stressing the same area.
Pressing the adhesive matters
After application, I gently press and smooth the adhesive around the sensor, taking care not to disturb the sensor itself. This encourages full contact between the patch and the skin, particularly around the edges where lifting often begins.
Freshly applied adhesive deserves a little consideration. If possible, I avoid immediately soaking it, covering it with lotion or heading into an extremely sweaty workout. I follow the water-exposure instructions for my exact device rather than assuming every sensor model is identical.
When I use an overpatch
An overpatch adds another adhesive layer around the sensor. Some people apply one from the beginning; others wait until the original edge begins to lift.
The best approach depends on the sensor model, the approved overpatch and how the skin reacts. A patch should not cover any part that the manufacturer says must remain uncovered, and it should not pull the sensor out of position.
If an edge is already loose, I do not push dirty or rolled adhesive back onto the skin and expect it to recover. I make sure the area is dry and use an appropriate patch according to its instructions.
Showers, swimming and sweaty days
Water is not the only issue. Repeated rubbing with a towel can lift an edge that survived the shower perfectly well.
After bathing or swimming, I pat the area dry instead of scrubbing it. I also try to avoid leaving wet clothing pressed against the patch for long periods.
During exercise, sweat can collect beneath loose adhesive. Breathable clothing and a site away from tight seams may help. If I know a holiday, heatwave or active weekend is coming, I plan the sensor change and supplies accordingly rather than hoping one tired edge will survive everything.
Skin protection comes before perfect adhesion
Stronger is not always better. If the skin becomes itchy, blistered, painful, swollen or increasingly red, keeping the sensor attached is no longer the only concern.
Barrier products and alternative adhesives can help some people, but ingredients and device instructions vary. They may also affect insertion or adhesion if used incorrectly. Anyone with recurring reactions should ask their diabetes team, pharmacist or dermatology professional for individual advice.
When the sensor is no longer secure
I never try to reinsert a sensor filament or push a partly detached sensor back into the skin. If the sensor has moved, is painful, produces unreliable readings or is no longer safely attached, I follow Dexcom’s removal and replacement guidance.
For technical problems or replacement enquiries in the UK, Dexcom provides product support. It can be useful to keep the sensor details and any relevant photographs until the query is resolved.
The goal is not to create an indestructible patch. It is to give the adhesive a clean, dry surface, protect it from predictable friction and know when skin health or sensor safety matters more than squeezing out one more day.