How do I stop insulin pump infusion set tunneling?

Hey Jason, smelling that distinct "Band-Aid" scent of insulin when you're supposed to be absorbing it is incredibly frustrating, especially when it's followed by a stubborn high blood sugar! What you're dealing with is a very common mechanical issue among active pump users.

Insulin pump infusion set tunneling happens when the tissue around your cannula gets slightly disturbed, usually from physical movement, sports, or bumping the site. Instead of absorbing into your subcutaneous tissue, the insulin essentially follows the outside of the tiny tube (the cannula) right back up the "tunnel" to the surface of your skin. This is why you end up smelling it and why your blood sugar spikes—the insulin is pooling on top of your skin rather than doing its job inside your body.

This issue is notoriously common with flexible Teflon (plastic) cannulas. Because the material is so smooth, the constant micro-movements of your muscles during a workout can easily wiggle the cannula just enough to break the seal between it and your tissue.

To fix this, many active people in the community find success by switching to a steel needle infusion set (like the TruSteel or Sure-T). Because they are rigid and sit at a 90-degree angle, they stay planted firmly in the tissue and don't flex or wiggle when you move, which almost completely eliminates the tunneling issue.

If you prefer to stick with your current plastic sets, try anchoring them down better. You can use the "plastic sandwich" method: apply an IV prep pad or clear adhesive patch under the site before you insert it, and then place another overpatch on top. This locks the entire plastic housing against your skin so it can't tug on the cannula while you exercise.