If your doctor has mentioned a continuous glucose monitor, or the box is already sitting on your table unopened, it's normal to feel two ways about it. Part of you may want the extra information, and part of you may worry it'll become one more way to feel judged, right there on a graph in color. I've sat through a lot of first days with sensors, and both feelings make sense. Let's go over what a CGM is, how it works, and how to use it without letting it take over your day.
What is a CGM?
A CGM, or continuous glucose monitor, is a small sensor you wear on your skin. It checks your glucose (blood sugar) all day and night and sends the numbers to your phone or a small reader. It shows you patterns, but it isn't a cure. It helps most when you and your care team use what it shows to make decisions together.
NIDDK's CGM patient guide describes three parts: the sensor under your skin, a transmitter that sends the numbers, and a screen where you read them, often your phone. Most sensors are replaced every 7 to 14 days, and some implanted ones last longer.
I'm Cheri Sacks, a registered nurse and a Certified Diabetes Care and Education Specialist. I won't recommend a brand, because that choice belongs to you, your prescriber, and your insurance. I work alongside your doctor, never instead of them.
Who can a CGM help?
A continuous glucose monitor can help even if you don't take insulin, especially with education beside the numbers.
The ADA's 2026 technology chapter says a CGM can help from the time of diagnosis on. That includes people who take insulin, people who take other diabetes medicines that can cause lows, and anyone whose care it helps. So it isn't only for people on insulin, but it also doesn't mean every person with type 2 diabetes has to wear one.
The ADA also says a sensor works best alongside education. Looking at your report with someone is much more helpful than staring at colored lines alone on your phone. A CDCES can go over your patterns with you without turning them into a lecture.
How does it actually work?
A CGM reading runs a few minutes behind your blood, so a finger stick still matters when something feels off.
The sensor reads the fluid between your cells, which doctors call interstitial fluid, rather than your blood. That fluid runs a few minutes behind your blood. So when your glucose is rising or falling quickly, a finger stick and a CGM can show different numbers, and that's normal. The CDC's CGM page explains it the same way: that fluid and your blood aren't exactly the same.
That's why it's still worth keeping a meter. Do a finger stick when you feel low, when the number doesn't match how you feel, or when your clinician has asked you to.
Most CGMs also show a small arrow next to your number, pointing up, down, or steady to show which way your glucose is heading. The arrow shows direction, but it isn't an instruction. Please never change your insulin because of one arrow unless you and your physician have already agreed on a plan for that. If they haven't, don't invent one at 2 a.m. Talk with your doctor first.
What do the numbers mean?
Time in range shows how your ordinary days are going, and lows always come first.
Time in range is the share of your day that your glucose stays inside your target zone. That zone is often 70 to 180 mg/dL (the unit your meter uses). For many adults who aren't pregnant, the goal is more than 70 percent of the day in that zone, with very little time below 70. That usually goes along with an A1C (your average glucose over about three months) under 7 percent, when that goal is safe for you (ADA 2026 glycemic goals). Older adults often have gentler targets, and yours is set with your physician.
When I look at a report with someone, we start with time below range, because lows need attention first. Then we look at time in range, and then at highs as a pattern, never as a scolding. I like time in range because it rewards ordinary days. You can have a bump at lunch and still have a great day overall.
A1C is still a lab test your clinician may order, and a CGM doesn't replace it. Instead, it shows the day-to-day details behind that three-month average. If the two don't seem to agree, that's a conversation to have with your physician.
Getting through the first week
Your first week with a continuous glucose monitor takes practice, from the alarms to keeping the sensor in place.
The first week is often the hardest, and the sticky patch takes getting used to. Skin under a patch for ten days can get irritated, so try these tips:
- Move the sensor to a new spot each time.
- Put it on clean, dry skin, because lotion under the patch can make it fall off.
- If you blister, itch, or weep, tell your clinician. There are barriers, overlays, and other brands that may work better for you.
Alarms are the other big adjustment. Most CGMs can beep or buzz when your number goes too high or too low, and those alerts can take over your day. A high alarm at 181 when your zone ends at 180 can make you dread dinner. You and your care team can set the alarms wider while you're learning.
Some people feel calmer with a CGM, especially when they see that a walk after dinner really did help. Others feel more anxious. If the graph is making you anxious, we can turn it down with fewer alarms and fewer checks, because the point is information, not a new job.
I remember a man who texted me a screenshot at 11:47 p.m. showing a spike, along with a long apology. The spike was from a birthday cake he'd already decided to eat, which we'd already agreed was fine. We put the phone down, and in the morning his week still looked like a normal week. One party isn't a character flaw, and late-night panic is a reason to change the alerts, not the person.
Coverage, and why you shouldn't go it alone
Whatever your coverage, keep your care team involved in how you use your CGM.
Some sensors are available over the counter now. Even so, using one safely while you take insulin or other medicines that can cause lows still belongs with your care team.
Insurance coverage changes often and can be confusing. Ask your prescriber's office who submits the request, and ask your pharmacy what your plan actually covers. If you don't have a clinician involved yet, start there rather than at a checkout page. How to work with a health coach and your doctor has words you can use at your visit.
A final thought
A CGM works best as a flashlight, not a judge. Used kindly, it shows you what your days are already doing, and numbers are information, not a report card.
I offer diabetes education and coaching, one-to-one, and in a group when that's a better fit. We can look at your patterns together without living on the graph, though I'll never change your insulin. The first conversation is a free call, and you can book that here. Bring the unopened box if that's where you still are.
You don't need to do more. You need to do what works for your body.
With Care, Cheri Sacks, R.N., C.D.C.E.S. Your Neighbor, The Nurse
Education. Never change insulin from a sensor reading without your prescriber. Please talk with your physician before you change a medicine, a meal plan, or an activity plan.
Related reading
Frequently asked questions
Sometimes. Check with a finger stick when you feel low, when the CGM number does not match how you feel, or when your team told you to. The CGM reads a few minutes behind your blood. Your body is not wrong when it disagrees with a graph.
Insulin is the strongest reason. The 2026 guidance is wider: it also covers other diabetes medicines that can cause lows, and any treatment where a CGM helps. Ask your physician where you fit. It is a fair question at type 2 visits now.
For many adults, more than 70 percent of the day between 70 and 180, very little below 70. Age, other illnesses, and a history of lows can change that. Yours is set with your clinician, not with a stranger's screenshot.
The device does not. Decisions do. Education plus CGM tends to beat a sensor alone. If nobody looks at the report with you, the graph is not doing its job.
Some sensors are over the counter. Using them on insulin or on medicines that can cause lows still belongs with your team. Please talk with your physician first.
Then we talk about whether the information is worth the itch, or whether finger sticks and a meter still serve you. Not every useful tool is the right tool for your arm.
