Tandem t:slim X2: How It Works, Features, and the Latest Updates
Key takeaways:
- The t:slim X2 insulin pump is a small, tubed pump with a color touchscreen.
- Users can control the pump directly from the device or using an iPhone or Android smartphone app.
- The t:slim X2 is part of the Control-IQ+ AID system, which automates insulin delivery in combination with a CGM – the Abbott Freestyle Libre 2 Plus/3 Plus or the Dexcom G6/G7.
What is the t:slim:X2?
The t:slim X2 is a small, tubed pump with a color touch screen. From the screen, you can view CGM readings, bolus, and make settings changes.
The pump is also part of the Control-IQ+ automated insulin delivery (AID) system. The t:slim X2 integrates with the Dexcom G6 and G7, and Abbott's FreeStyle Libre 2 Plus/3 Plus.
Control-IQ+ is FDA-approved for ages 6 and older, for type 1 diabetes, and those 18 and older with type 2.
The t:connect mobile app can be used on iPhone and Android smartphones to view pump and CGM data and deliver boluses. The pump can hold up to 300 units of insulin.
The t:slim X2 is watertight, but not waterproof, and should not be worn while swimming or in hot tubs or saunas. The device uses a rechargeable battery.
t:slim:X2 operating modes
Based on CGM readings and prediction of blood sugar 30 minutes in the future, the Control-IQ+ algorithm increases basal insulin if blood sugar is predicted to rise above 160 mg/dL and delivers correction bolus doses, up to once per hour, if glucose is expected to rise above 180 mg/dL.
The system uses a range of targets based on the time of day or expected activities, including:
- Automated basal rate adjustment during the day (including after meals): The system targets a range of 112.5-160 mg/dL.
- Automated basal rate adjustment at night: The algorithm becomes more aggressive at night and tries to arrive at 112.5-120 mg/dL by morning.
- Exercise activity mode: Users can manually choose a higher target range of 140-160 mg/dL to avoid low blood sugar during or after exercise.
- Sleep activity mode: Users can set programmed sleep schedules with a target range of 112.5–120 mg/dL (or you can enter this mode manually).
Control-IQ+ works to keep users in range (between 70-180 mg/dL) based on a combination of strategies. When the predicted CGM value in 30 minutes is:
- Above 160 mg/dL, basal insulin rate increases
- Above 180 mg/dL, a correction bolus is given up to once per hour
- Between 112.5-160 mg/dL, default user settings are maintained
- Below 112.5 mg/dL, basal insulin decreases
- Below 70 mg/dL, basal insulin is turned off
Control-IQ+ will give about 60% of a full correction bolus with a target of 110 mg/dL. These boluses occur in addition to the automatic basal rate and can help move blood sugar back into range even when meal boluses are missed. Users still need to bolus for meals.
How much does the t:slim:X2 cost?
Many health insurance plans cover the cost, or a percentage of the cost, for a new pump during the warranty period. Tandem warranties are for four years. Without insurance, the t:slim X2 costs $4,000. Tandem says the average customer with insurance pays less than $50 monthly, including supplies.
Coming features for the t:slim X2
Tandem announced in June 2025 that its AID systems will integrate a future glucose sensor from Abbott that also monitors ketones, which hopefully will greatly reduce the risk of diabetic ketoacidosis, a potentially serious complication that occurs when insulin levels are too low.
Learn more about Tandem AID systems here: