Medtronic MiniMed 780G

How the algorithm works

The Medtronic 780G system has three components:

• Medtronic 780G pump
• Guardian Sensor 3, Guardian 4, or Simplera
• The SmartGuard algorithm inside the pump

Key principles of how the algorithm tends to behave:

• The algorithm auto-calculates basal rates and correction factors
• Basal insulin increases when glucose is rising
• Auto-corrections are delivered aggressively every five minutes when glucose is rising quickly (above 6.7 mmol/L / 130 mg/dL) and basal increases are not enough
• Basal insulin decreases and suspends if glucose is predicted to go low
• The default target is 5.5 mmol/L (100 mg/dL), adjustable upwards to 6.1 or 6.7 mmol/L if needed

Starting settings

The algorithm needs your weight, average total daily insulin dose, carbohydrate ratios, and active insulin time. SmartGuard then updates continuously in the background.

The system requires 48 hours of wear before SmartGuard can be activated, so it can learn insulin sensitivity patterns.

The target level on the 780G can be adjusted, but for maximising time in range it is generally left at 5.5 mmol/L (100 mg/dL). Having basal rates and correction factors kept current is recommended for situations requiring a return to manual mode. Once these are set, the most common ongoing adjustment is carbohydrate ratios.

Starting an AID system can be broken down into two phases:

Download the How to Survive and Thrive Guide — 780G summary. A more comprehensive onboarding workbook is also available: 780G Workbook.

Tips and practical approaches

Strong time in range on the 780G tends to combine the algorithm with good underlying habits:

• Three balanced meals
• Accurate carbohydrate counting
• Bolus insulin 10–20 minutes before eating
• Being active for 10–15 minutes after eating
• Rotating cannula sites

Follow these and you may find: 99 Problems But Highs Ain’t One (download/share)

Other practical points to be aware of:

• Suspending the pump when disconnecting (showers, sport, and similar) is the recommended approach per device guidance
• Having manual mode settings — basal rates, correction factors, and target level — kept current is recommended for situations where SmartGuard is not available

Preventing and managing hypos

The algorithm tends to prevent many overnight hypos, but hypos will still occur — particularly if bolus insulin is too high for a given situation or exercise is unplanned.

Hypo treatment amounts often need to be smaller than before AID, because the algorithm tends to have reduced or stopped insulin at least 30 minutes earlier.

It is also worth considering a pre-emptive response if glucose is 4.0–6.0 mmol/L (70–110 mg/dL) and trending down.

The hypo treatment chart below is based on weight — the example shown is for a 30 kg person. Download the Survive and Thrive — 780G guide and enter your own weight to generate a personalised version.

Download the 780G hypo chart to use directly.

High-fat meals

From the Mealtime Insulin Guide, we know that high-fat meals with carbohydrates (pizza, takeaways) tend to need additional insulin due to delayed gastric emptying.

When active insulin time is set between 2–3 hours, SmartGuard generally handles the delayed rise fairly well.

A common starting approach for pizza is to enter all the carbohydrate upfront and allow SmartGuard to respond to the delayed rise. This is a population-average starting point — individual responses vary significantly and CGM data is the best guide to what works.

Exercise

There is a quick method and a more comprehensive planned method.

The quick method

Turn on Exercise mode before starting — ideally 90 minutes beforehand. Then take small carbohydrate top-ups every 20 minutes as needed.

Avoid large carbohydrate loads all at once: glucose may spike and the algorithm may increase insulin, raising hypo risk.

How many grams every 20 minutes? It depends on body weight. The example below is for a 50 kg person. Download the Survive and Thrive — 780G guide and enter your own weight to generate a personalised chart.

Download the exercise charts: mmol/L version and mg/dL version.

The comprehensive planned method

To use this approach, work through the Exercise Guide to understand exercise types, bolus reductions, and how to adapt plans after trials.

The T25/T25 table below tends to make more sense once you have read the exercise guide. The AID and Exercise Consensus Guideline is also worth reading — the infographic under the T25/T25 grid is especially helpful.

This downloadable exercise planning tool for the 780G makes creating and adapting exercise plans easier.

Explore the algorithm

The AID System Explorer generates exploratory output ranges for the 780G based on your TDD, weight, and responsiveness level. The detailed explainer explains how the 780G uses shorter AIT and lower targets to lower IOB visibility — and the trade-offs this creates during exercise.