Support — Blood Sugar

Getting started

Blood Sugar is a log for glucose, insulin, carbohydrates and the rest of diabetes care, with charts that show how your days go and a report for your doctor.

It runs on iPhone and iPad with iOS 18 or later. There is no account to create.

The first launch asks a few questions and sets the app up from your answers:

What are you managing? Type 1, type 2 or gestational diabetes, prediabetes, or no diagnosis. This sets a starting target range, shown with its source.
How do you read your numbers? mmol/L or mg/dL, and carbohydrates in grams or exchange units.
What is your target range? Adjust the low and high ends.
How do you measure? Finger prick, a sensor (CGM), or both.
Do you take insulin? None, basal only, basal and bolus, or a pump.
What should I remind you about? A morning check, and a check after meals.
Apple Health — allow it to read and write your records.

The tabs

Summary — your latest reading, the chart for the day or any period, today’s checklist and tiles with your averages.
History — everything you logged, newest first.
Food — every helping you have eaten, with its carbohydrates.
Settings — targets, units, treatment, devices and data.
+ — opens the log from anywhere.

Logging

Tap + to open the log. It works like a calculator: choose what you are typing with the chips at the top, type the number, and tap Save.

Glucose — the reading. Below it, Meal time tags it as Fasting, Before or After a meal, or leaves it untagged.
Insulin — units, as Basal or Bolus. This chip is hidden if you turn Insulin off in Settings.
Carbohydrates — what you ate (see Adding food below).

Switching chips keeps what you typed, so one Save logs a reading, a dose and a meal together as one moment. Save stays grey until the numbers are plausible: glucose between 0.6 and 33.3 mmol/L (11 and 600 mg/dL), insulin up to 300 U.

The time follows the clock. To log something earlier, tap Date & Time at the top.

After you save a main meal with After meals reminders on, Blood Sugar reminds you to check your glucose later. A new reading cancels that reminder.

Logging from anywhere

Siri and Shortcuts:
- “Log an entry in Blood Sugar” opens the log.
- “Dictate to Blood Sugar” lets you say it in one sentence, such as “7.2, six units basal and a potato”. Blood Sugar reads it back and logs it when you say yes. With Apple Intelligence on iOS 26 or later it understands more ways of saying things. Anything it can’t fill in opens in the app.
- “Log oatmeal in Blood Sugar” logs a food you have eaten before, with its saved figures.
Home Screen: press and hold the app icon for Glucose, Insulin or Scan food.
Control Center (iOS 18 or later): add the Glucose, Insulin and Scan food buttons.

Weight

Tap the Weight tile on Summary (add it back under Tiles if you removed it), and enter your weight in kilograms under Log weight. It is saved to Apple Health too.

Adding food

On the Carbohydrates chip, choose the meal (Breakfast, Lunch, Dinner or Snack; Blood Sugar suggests one from the time), then add food with one of three buttons:

Food — pick something you have eaten before, with its saved carbohydrates.
Camera — photograph the plate, a nutrition label or a barcode (see The meal scanner).
Add — type a name and the carbohydrates. With Plus, typing also searches Open Food Facts and USDA. Typing the digits under a barcode looks it up.

Each dish becomes a row in the plate; tap one to correct it. A total marked “~” includes figures estimated from a photo. Carbohydrates are shown in your chosen unit: grams, carb units (10 g), bread units (12 g) or carb choices (15 g).

The meal scanner

Open the camera from the log, or with Scan food on the Home Screen or in Control Center. A switch at the bottom chooses the mode:

Photo (free) attaches the picture to the meal, without reading it. Type the carbohydrates yourself.
AI (Plus) reads what the camera sees:
- A plate comes back as dishes with their weight and carbohydrates.
- A nutrition label becomes one line, per serving where the label gives it.
- A barcode is read live by the camera, then looked up in the foods you’ve eaten and in Open Food Facts and USDA. A worn barcode can be typed under Type the number.

Nothing is saved until you add it. Weights and carbs from a scan are an estimate: correct them to what is actually on your plate. The dose is always yours to decide.

How photos are read: for a plate or a label, one photo goes over an encrypted connection, through a proxy we run, to Google Gemini, which reads it. Neither the proxy nor we keep it. The photo stays with your meal, on your devices and in your iCloud. A barcode is decoded on the device; only its digits are looked up. Without a connection, plates can’t be read, a nutrition label is read on the device instead, and a barcode works if you have eaten that food before.

Plus includes 20 plate and label scans a day. You can use up to 5 in a row, and one more comes back about every 72 minutes. Barcodes don’t count. If it says the reader is busy, wait a few minutes or type the carbohydrates in.

The Food tab

Food lists every helping you have eaten, day by day. Use the chips to choose:

Meals — any of breakfast, lunch, dinner and snack.
Order — Recent, A–Z, Z–A, fewest or most carbs.
Period — last week, month, 3 months, year, or your own dates.
Basis — per portion or per 100 g.

Swipe a row right to Log again, left to Edit or Delete. Tap a meal’s heading to open the whole meal.

With the glycemic index on (Settings › Units & display › Glycemic index), each food shows how much it is likely to raise your glucose. Once you have readings before and after eating it, that is your own measured rise. On iOS 26 or later with Apple Intelligence, a missing index is guessed on the device.

Summary

Periods and charts

Choose the span with D, W, M, Y or Max, or tap the calendar for your own dates. The arrows step to earlier and later periods. Drag along the chart to read any moment. In the day view, tap a meal on the chart to see the reading before and after it, the rise, the carbs and the dose.

Tiles

The tiles show your averages for the period: HbA1c, average glucose, bolus, basal, carbohydrates, glycemic load and weight, and optionally steps and active energy. Tap a tile for its chart and what the number means.

To change them, tap the last tile, Tiles. Drag to reorder, swipe to remove, and add from Not shown. You can also touch and hold a tile and drag it.

The HbA1c tile is estimated from your readings once the period holds at least 30 readings on 14 different days, so it shows in the month view and longer. A lab HbA1c from the last four months is shown instead, with the estimate beside it when the two differ noticeably.

Today

In the day view, Today lists the medicines due, and you tick each one as taken.

History

History shows every reading, dose, meal, medicine and weight in time order. From the menu at the top:

Group by Day, Week, Month, Quarter or Year. Grouped rows show averages, time in range, carbs and units per day.
Pick a day… jumps to one date.

Search finds meals and values. Sensor readings are thinned to one per interval to keep the list readable (see Using a CGM).

Correcting and deleting

Tap any entry in History, or a meal on Summary, to open it in the log. Change what you need and save, or tap the bin to delete it. Deleting also removes what Blood Sugar wrote to Apple Health.

Targets and units

Settings › Treatment › Target range sets four limits: Critical Low, Low, High and Critical High. Readings between Low and High count as in range. Set your own range with your doctor.

Settings › Units & display chooses the glucose unit (mmol/L or mg/dL) and the carb unit. Changing a unit only changes how numbers are shown; nothing you logged is altered.

Medicines

Settings › Treatment › Medicines lists what you take. Tap + to add one:

Name and Strength, as printed on the box.
Repeat and Times a day.
On the daily checklist, so it appears under Today.
Show in History. Turn it off for a medicine you already log as insulin, to avoid double entries.
Reminders at the times you choose, with Ask again until taken.

Medicines are counted as taken or not, never summed. A medicine you stop keeps its history.

Reminders

Settings › Treatment › Reminders:

After meals — a glucose check a set time after a main meal (1 to 3 hours). Skipped for snacks, and cancelled if you have already measured.
Morning check — a fasting reading before breakfast, at the time you choose.
Medicines — the reminder times of each medicine, and how soon to ask again if you haven’t ticked it. Tap Taken right in the notification.

Allow notifications when asked. If they are off, the screen shows a button to open Settings. Reminders never show a reading or a dose.

Care plan and lab results

Settings › Treatment › Care & results has two parts.

Plan

Tasks to keep on top of: tests to book, prescriptions to collect, supplies to reorder, appointments. Tap + for a new task, or From suggestions for common ones such as an HbA1c test every three months or a yearly eye screening.

Each task has a kind, a due date, an optional repeat, Add to Calendar and Remind me. A task linked to a lab test closes when you save its result.

Results

Tap + › Lab result to add HbA1c, fasting glucose, cholesterol, kidney tests, blood pressure, TSH, vitamin D, liver tests or any other result. Enter the value and unit, copy the reference range from your report, and attach a photo or a PDF of it. HbA1c and fasting glucose are marked against WHO ranges.

Ketones are added here too, from a blood meter in mmol/L or from a urine strip.

Apple Health

Blood Sugar reads and writes glucose, carbohydrates, insulin and weight, and reads steps and active energy. Everything already in Health comes in on the first sync, and new records keep flowing both ways.

Settings › Devices & data › Apple Health shows the status, with Sync now and Open Health. To change what Blood Sugar may read or write, open the Health app, tap your profile picture, then find Blood Sugar in the list of apps.

Ketones, lab results, medicines and care tasks stay in Blood Sugar. A record that came from another app, such as a sensor or a pump, can be corrected in Blood Sugar, but its copy in Health stays as that app wrote it.

Using a CGM

Blood Sugar doesn’t connect to your sensor. It reads what the sensor writes into Apple Health. Turn on writing to Health in your sensor’s own app (Dexcom, Libre or whichever you use), and its readings appear here.

A sensor can write 288 readings a day. Settings › Devices & data › Sensor (CGM) sets how many of them History shows: every 5 minutes, 30 minutes, hour or 4 hours. Averages, charts and time in range always use every reading.

The report for your doctor

Settings › Devices & data › Export for doctor builds a PDF with Plus:

Choose the dates, the Language, the Paper (A4, or Compact to read on a phone) and the units.
Under What to include, switch food, glycemic load, insulin, averages by meal time, ketones, medicines and lab results on or off.
Tap Create PDF, then View report or Share report.

The report has a summary with time in range and the estimated HbA1c, then every day with its readings, food and insulin. It is made on the device and stays there until you share it.

Backup and moving your data

Your records sync through iCloud on their own. To keep a copy of your own, or move to a different Apple Account, use Settings › Devices & data › Data:

Export all data saves everything, photos included, to one file.
Import from file adds what is in a backup to this device. Records already here are updated and nothing is deleted, so importing the same file twice changes nothing.

Sync between devices

With iCloud on, your log, foods, medicines, care plan and lab results sync to every iPhone and iPad on your Apple Account, through your own iCloud. The Summary tile layout, theme and sensor interval are set on each device.

Settings

Plus — your plan; the Plus screen it opens has Restore purchases.
Units & display — glucose unit, carb unit, glycemic index, theme (System, Light or Dark) and language.
Treatment — target range, insulin on or off, medicines, reminders, care and results.
Devices & data — Apple Health, sensor, export for doctor, and backup.
Health basics — short notes on glucose, HbA1c and time in range, with their WHO sources.
Rate Blood Sugar, More Apps and About, with the food data credits, the privacy policy and the app version.

Blood Sugar Plus

Free, you get everything for logging and understanding your numbers: glucose, insulin, food, weight, ketones, medicines, the care plan and lab results, every chart and History, the camera in Photo mode, Apple Health, iCloud sync, backup, reminders and Siri.

Plus adds three things:

The AI meal scanner — plates, barcodes and nutrition labels.
The food database — search Open Food Facts and USDA.
The report for your doctor as a PDF.

Plus is a yearly plan with a free first week if your Apple Account is eligible, or a monthly plan. The Plus screen shows the prices in your country.

Restoring Plus

Open Settings, tap the Plus card, then Restore purchases at the bottom. Use the Apple Account you bought it with. If the scanner says your subscription couldn’t be confirmed, restoring fixes it.

Cancelling

In the Settings app on iPhone, tap your name, then Subscriptions, then Blood Sugar. Plus stays on until the end of the period you paid for. To avoid being charged, cancel at least a day before the free week ends.

A note on medical use

Blood Sugar is a logbook and an information tool. It doesn’t diagnose, treat or prescribe, and it doesn’t calculate insulin doses. Carbohydrates estimated from a photo are approximations. Reference figures come from World Health Organization fact sheets and describe populations, not you. Targets, doses and treatment decisions are set with your doctor. In an emergency, contact your local emergency service.

Frequently asked questions

Do I need an account?

No. There is no sign-up. Your log lives on your devices and in your own iCloud.

Does it sync between devices?

Yes. With iCloud on, your log, foods, medicines, care plan and lab results sync to every iPhone and iPad on your Apple Account.

What is free and what is Plus?

Everything for logging is free: glucose, insulin, food, weight, ketones, medicines, lab results, every chart and History, Apple Health, sync, backup, reminders and Siri. Plus adds the AI meal scanner, the Open Food Facts and USDA food database, and the PDF report for your doctor.

Does it work with Apple Health and my CGM?

Yes. Blood Sugar reads and writes glucose, carbohydrates, insulin and weight, and reads steps and active energy. A sensor that writes its readings to Health shows up automatically.

Is my meal photo stored anywhere?

Not by us. For a plate or label, the AI reader sends one photo through our encrypted proxy to Google Gemini, which reads it; neither the proxy nor we keep it. The photo stays with your meal, on your devices and in your own iCloud, in both Photo and AI mode.

How many meals can I scan?

Plus includes 20 plate and label scans a day. You can use up to 5 in a row, and one more comes back about every 72 minutes. Barcodes don’t count. Offline, labels are read on the device and a barcode works for food you have eaten before.

Can I log by voice?

Yes. Say “Dictate to Blood Sugar” and tell it the reading, the dose and what you ate in one sentence. It reads it back and logs it when you say yes.

Why doesn’t Summary show my HbA1c?

The estimate needs at least 30 readings on 14 different days within the period, so it appears in the month view and longer. A lab HbA1c from the last four months, added under Care & results, is shown instead.

How do I give my doctor my data?

Settings › Devices & data › Export for doctor builds a PDF with time in range, the estimated HbA1c and every day’s readings, food and insulin, in the language and units you choose. It is part of Plus.

How do I restore Plus?

Open Settings, tap the Plus card, then tap Restore purchases at the bottom. Use the Apple Account you bought it with.

How do I cancel?

In the Settings app on iPhone, tap your name, then Subscriptions, then Blood Sugar. Plus stays on until the end of the period you paid for.

Contact

Write to sandoya1101@gmail.com. Every message is read and answered by the person who makes Blood Sugar, usually within a day or two.

For a bug, it helps to say what you did and what happened instead, and to include your device, its iOS, iPadOS, macOS or watchOS version, and the app version shown at the bottom of Settings.