① Get a CGM ready
maru's plan price doesn't include the sensor itself — you'll source one separately. Check compatible devices, your phone, and how to connect them before you start.
maru / Home
your first sensor
So, what's a CGM actually like?
One ordinary meal, and what happens after it.
A small sensor on your body is the doorway to seeing how you respond.
a little closer to your body
While you're wearing one, what happens after a meal gets recorded.
A CGM is a medical device that continuously measures glucose in the interstitial fluid just under your skin. Lined up against when you started eating, it lets you look back at how your body responded afterward.
maru connects those readings to your meal photos and everyday logging, and turns them into a report you can read back. Sleep and activity from Apple Watch add useful background — but seeing your glucose after a meal still requires a CGM of your own.
② Learn how to apply it, from the official guide
Wearing a CGM means inserting it just under the skin. Comfort varies from person to person, so we can't promise it won't be uncomfortable. Check the actual steps in your device's official guide.
③ Log your everyday meals
Save the time you ate and a photo, then look back at what comes in. One try won't settle everything — it's a chance to find what you want to check next.
getting started
Getting a CGM, and connecting it to maru.
Here's the general path — how a CGM connects to maru, and what to check before you buy.
How it gets to maru
Your CGM's official companion app is where you check your own readings, and where you turn on syncing to Apple Health. maru reads the glucose values that have been shared to Apple Health, and lines them up with your meal log so you can look back together.
On your iPhone, open the Health app and check that sharing from your CGM's app is turned on. maru only reads what's already been shared to Apple Health — it doesn't connect to any device directly.
What to check before you buy
Wear duration, warm-up time, and where you attach it all vary by device. Check your specific model's official page for the exact numbers rather than assuming. Confirm your phone is on the compatibility list, and check maru's own requirements too, before you buy.
maru doesn't sell CGMs. Look for compatible devices through the manufacturer's official site, your prescribing clinic, or a local pharmacy.
CGMs are medical devices with a defined set of people they're intended for. Check with a medical professional whether one is right for you, and follow the manufacturer's instructions for use.
service + sensor
The first stretch: about ¥10,000, as a rough guide.
Assume the 1-month plan at ¥3,780 and one sensor at an assumed ¥6,000, and the total comes to about ¥9,780. How long your subscription runs and how many days a sensor can record are two different things.
yen / sensor
Enter a whole number between 0 and 100,000 yen.
Start with one month
1-month plan ¥3,780
+ 1 sensor's worth
CGM coverage: about 10 days
Six check-ins a year
12-month plan ¥25,800
+ 6 sensors' worth
CGM coverage: about 60 days / year
Twelve check-ins a year
12-month plan ¥25,800
+ 12 sensors' worth
CGM coverage: about 120 days / year
The assumed sensor price of ¥6,000 is a budgeting placeholder, not a guaranteed sale price — actual prices vary by retailer and over time. The total shown covers only the tax-included service fee and the sensor cost you enter; shipping and similar costs are separate. This assumes each sensor lasts about 10 days before it needs replacing.
6 sensors works out to about one every two months; 12 works out to about one a month. Neither figure means you're expected to measure year-round, and neither is a medical recommendation for how often to wear one. Talk with a medical professional about whether — and how often — you should wear a CGM.
The service renews automatically at the end of each billing period. The free trial is limited to one per eligible account. See the pricing page for the conditions under which billing begins from the moment you sign up.
Pricing and how to sign upbefore you begin
Want to read one before you begin?
If a report like this makes you want to start logging, that's worth knowing before you commit. See for yourself, in a sample built from real logging.
Read a sample of the report you'd get