At $10-20 per sensor day, losing a sensor early is frustrating. These evidence-based tips extend adhesion and reduce premature failures across Dexcom and FreeStyle Libre.
Site Preparation Is Everything
Clean skin at the application site is the single biggest factor in sensor longevity. Use an alcohol wipe and let it dry completely — at least 30 seconds. Do not apply on freshly moisturized or sunscreened skin.
Shaving the Application Site
Hair under a sensor adhesive significantly reduces adhesion. Shave the back of the arm (or whatever site you use) the night before insertion, not immediately before — fresh shaving can irritate the skin and increase reaction risk.
Skin Tac: The Most Effective Adhesive Booster
Skin Tac wipes (available on Amazon, ~$15 for 50 wipes) applied to the skin before sensor insertion dramatically extend adhesion. Let the Skin Tac dry to a slightly tacky feel before applying the sensor. Most users with sweating or adhesion issues resolve them with Skin Tac alone.
Reinforcing Edges Mid-Wear
If edges start to lift after several days, apply a small piece of Tegaderm or Simpatch over the sensor edges (not the center). This extends adhesion without creating air pockets under the sensor that cause inaccurate readings.
Showering, Swimming, and Hot Tubs
Both G7 and Libre 3 are waterproof to 8 feet for 24 hours. Brief showers are no issue. For swimming, apply a Simpatch or Tegaderm overlay. Hot tubs (high heat + chemical exposure) can loosen adhesive faster — limit exposure or use extra adhesive support.
Temperature Extremes
Cold weather (below 40°F / 4°C for extended periods) can stiffen the adhesive and cause the sensor to lift. Warm weather and humidity have the opposite effect on adhesion — sensors hold better but sweat can eventually lift edges. Skin Tac addresses both extremes.
What to Do With a Failed Sensor
Both Dexcom and Abbott have replacement programs for failed sensors within the normal wear period. Contact customer support with the sensor lot number — replacements are typically provided at no charge for one-time failures.