InPen is a reusable smart insulin pen made by Medtronic that connects to a smartphone app via Bluetooth. Unlike a standard insulin pen, which simply delivers a dose, InPen automatically logs every injection, tracks how much insulin is still active in your body, and calculates suggested doses for meals and corrections. It’s FDA-cleared for people with type 1 or type 2 diabetes aged 12 and older.
How InPen Differs From a Regular Insulin Pen
A traditional insulin pen is purely mechanical. You dial a dose, inject, and that’s it. Keeping track of when you last dosed, how much insulin is still working, and what your next dose should be is entirely up to you, often with pen-and-paper logging or mental math.
InPen automates all of that. The pen pairs with a companion app (available on both iOS and Android) that records the exact time and amount of each dose. It calculates meal and correction doses based on your personal insulin settings, sends reminders if you miss a dose, and even monitors the temperature of the insulin inside the pen. If the pen detects a temperature extreme that could degrade your insulin, the app flags it so you know to replace the cartridge. The pen also allows dosing in half-unit increments, which gives finer control than many standard pens offer.
Compatible Insulins
InPen works with three rapid-acting U-100 insulin cartridges: Lilly Humalog, Novo Nordisk NovoLog, and Fiasp. All three must be the standard 3.0 mL pre-filled cartridge format. The pen does not accept pre-filled disposable pen bodies or vials. You can also manually log long-acting insulin doses in the app and set reminders for your basal injections, but the pen itself is only designed to deliver rapid-acting insulin.
What the App Actually Does
The InPen app is where most of the “smart” features live. At its core is a built-in dose calculator. You enter how many carbs you’re about to eat, and the app combines that with your current glucose reading, your personal carb-to-insulin ratio, your correction factor, and your target glucose to suggest a dose. Critically, the calculator also accounts for “active insulin,” the insulin from your last injection that’s still lowering your blood sugar. This helps prevent dose stacking, one of the most common causes of unexpected low blood sugar in people on multiple daily injections.
The calculator adjusts its approach depending on the situation. If your glucose is above target and you dosed within the last two hours, it subtracts active insulin from the correction portion of the dose so you don’t over-correct. If your glucose is below target, it reduces the food dose accordingly. And if you don’t have a glucose reading available at all, it simply bases the suggestion on carbs alone. You always have the final say on how much to inject.
CGM Integration
The app can pull glucose data directly from compatible continuous glucose monitors, removing the need to manually type in your blood sugar. It integrates in real time with the Medtronic Guardian Connect CGM and the Dexcom G6. It also works with certain Bluetooth-enabled blood glucose meters. When a CGM is connected, your glucose reading feeds automatically into the dose calculator, and the app can display your glucose trend alongside your dosing history for a clearer picture of how your insulin is working throughout the day.
All of this data can be viewed through Medtronic’s CareLink portal or through an Insights Report, which you can share with your healthcare team at appointments.
Practical Details
Each InPen is designed to last one year before it needs to be replaced. It uses a built-in battery that lasts the full year, so there’s nothing to charge or swap out. The pen is about the same size as a standard reusable insulin pen, and you replace the insulin cartridge whenever it runs out, just as you would with any reusable pen.
InPen requires a prescription. Some insurance plans cover it as a pharmacy benefit, though coverage criteria vary. Kaiser Permanente, for example, requires that the prescription come from an endocrinologist or diabetologist. Your insurance may have similar requirements or different ones entirely, so checking with your plan before filling the prescription is worth the effort.
Who Benefits Most
InPen is designed for anyone on multiple daily injection therapy who wants tighter tracking without switching to an insulin pump. It’s particularly useful if you struggle with dose logging, forget whether you already took a correction, or find carb-ratio math tedious at every meal. Parents managing insulin for a teenager may appreciate the automatic logging and the ability to review dose history remotely through shared reports.
People who already use a CGM get the most out of the system, since the automatic glucose feed eliminates manual entry and gives the dose calculator better data to work with. But even without a CGM, the active insulin tracking and dose reminders address two of the biggest day-to-day challenges of injection-based insulin therapy: accidentally stacking doses and simply forgetting to take them.