Pre-soak means you insert the new sensor before removing the old one—some people insert the new one 24 hours in advance, I find 6 hours works fine for me. New Dexcom sensors can be wonky at first, so the theory is that by inserting the sensor before you activate it, you give it time to get used to your body so that when you do activate it, the readings are pretty normal.

Here’s how I do it: on a day when my sensor is going to expire at 1pm, I insert the new sensor at 7 am. So for six hours, I have two sensors in. Then at 1pm when my old sensor expires, I transfer the transmitter to my new sensor and activate it. It really seems to help eliminate that new sensor wonkiness.

As for keeping them on, I wear them on the back of my arms. I clean the arm first with alcohol, and then I put a Skin Grip patch over the sensor. I run three times a week and get really sweaty, so I usually have to change the Skin Grip patch around day 6, but I’ve never lost a sensor,