About a year ago, I tried a continuous glucose monitor (CGM) for the first time.
At the time, I was starting to worry about my blood sugar and the possibility of being labeled pre-diabetic. When over-the-counter CGMs became available, I ordered a one-month supply and decided to see what I could learn.
The problem was, I didn’t really know what to look for.
I wore the sensors, checked the app, and watched the numbers. But I didn’t know which numbers mattered, how often to check, or what changes were actually worth paying attention to.
Several months later, I was still frustrated with my blood sugar and my weight, so I decided to try again with a better plan. This time, I paid more attention to the goal behind the CGM — not just the sensor itself.
Some CGMs are designed mainly for diabetes management. Some are over-the-counter wellness tools. Some come with stronger apps, education, or coaching. And some may be better suited for weight loss than others.
If you’re trying to choose your first CGM, this guide will help you compare the most important things: your goal, the cost, the app, the support, and whether an over-the-counter or prescription CGM makes the most sense for you.
Medical Note: This content is for educational purposes only and reflects my personal experience and research. It is not medical advice. Always consult your healthcare provider before making health decisions based on this information. Read my full Medical Disclaimer here.
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What Is a Continuous Glucose Monitor (CGM)?
A continuous glucose monitor (CGM) is a small wearable sensor that tracks your blood sugar levels around the clock — not just at one moment in time.
It sits on the back of your upper arm and sends real-time data to an app on your phone. Instead of a single snapshot, you can see:
- How your glucose rises and falls after meals
- Which foods cause spikes — and which don’t
- How sleep, stress, and movement affect your levels
- Patterns that repeat day after day
For weight loss specifically, most people don’t realize how much blood sugar swings affect hunger, cravings, and fat storage — and most of us have no idea what our glucose is actually doing throughout the day. A CGM makes that invisible process visible.
I had no idea what my glucose was doing until I started wearing one — and that alone changed how I thought about food.
(Want a deeper dive? Check out my article: What Is a CGM — Continuous Glucose Monitor Explained)
OTC vs Prescription CGMs (What Beginners Should Know)
There are two main ways to get a continuous glucose monitor (CGM), and understanding the difference can help you figure out which path makes sense for you.
Over-the-Counter CGMs
Over-the-counter CGMs are available without a prescription. You can order them online or, in some cases, find them through retail sites like Amazon.
They are designed for general wellness and metabolic awareness, not diabetes management. Because you are buying directly, the pricing is usually easier to understand, and there is no insurance process to deal with.
Current over-the-counter options include Stelo by Dexcom and Lingo by Abbott. I started with Stelo, so that is the one I know best from my own experience.
Prescription CGMs
Prescription CGMs are ordered through a healthcare provider and are typically used for diabetes management.
Depending on your situation, insurance may cover part or all of the cost. If you are already working with a doctor because of blood sugar concerns, it is worth asking what your options are.
Which Is Right for You?
If your goal is weight loss and metabolic awareness, and you do not have a diabetes diagnosis, an over-the-counter CGM may be the simplest place to start.
If you have diabetes, take insulin, use medications that can lower blood sugar, or want to explore insurance coverage, talk with your healthcare provider first.
One thing both options may have in common: FSA and HSA funds can often be used, which can help offset the cost.
How To Choose the Right CGM (Step-by-Step)
Choosing a CGM is easier once you know what to compare. Start with these six things.
Step 1: Start With Your Goal
Before picking a device, get clear on why you want one.
Common goals include:
- losing weight
- reducing cravings or energy crashes
- learning which foods work better for your body
- watching blood sugar trends
- getting ahead of pre-diabetes concerns
Your goal will shape which device, app, and features matter most.
Step 2: Decide Between OTC and Prescription
For many beginners focused on weight loss, an over-the-counter CGM is the simpler place to start.
If you have diabetes, take medication that can affect blood sugar, or want to explore insurance coverage, talk with your healthcare provider first.
Step 3: Focus on the App
This is the part I wish I had paid more attention to the first time.
The sensor collects the data, but the app is where you see what is happening. Look for an app that makes it easy to connect your numbers to meals, movement, sleep, stress, and cravings.
Useful app features include:
- easy-to-read glucose graphs
- meal and activity logging
- clear summaries or insights
- a simple way to review past days
Step 4: Compare the Features That Matter
Do not get buried in every technical detail. Start with the basics:
- how long each sensor lasts
- where it is worn
- how comfortable it feels
- whether the adhesive holds well
- phone compatibility
- customer support
Two over-the-counter options beginners may compare are Stelo by Dexcom and Lingo by Abbott.
For a fuller comparison, you can also read Best CGM Devices for Weight Loss 2026.
Step 5: Understand the Cost
Do not just look at the price of one sensor. Look at the monthly cost, including how many days each sensor lasts, how many sensors you need per month, whether there is a subscription option, whether FSA or HSA funds can be used, and whether you can cancel easily.
Step 6: Read Real User Reviews
Before choosing a CGM, read reviews from people using it for the same reason you are.
Pay attention to comments about setup, comfort, adhesive, app experience, customer support, and whether people felt it was worth the cost.
Reviews from beginners are especially useful because they often mention the practical things you may not think about until you are actually wearing one.
Common Beginner Challenges
A CGM is not hard to use, but there are a few things beginners may not think about until they are wearing one.
Skin sensitivity: Some people notice mild irritation around the sensor site. This is usually from the adhesive, not the sensor itself. If you have sensitive skin, barrier wipes may help protect the area before you place the sensor. Hypoallergenic patches may also be worth keeping on hand.
Sensor coming loose: Sweat, showers, swimming, or high activity can loosen the adhesive over time. An overpatch can give the sensor extra support and help it stay in place.
Removing the sensor: Taking off a sensor can tug at your skin, especially if the adhesive is still holding strong. Adhesive remover can make removal easier and help with leftover sticky residue.
Making sense of the data: This is the part many beginners underestimate. The numbers are only useful if you know what you are looking for. Start with simple questions: What happened after that meal? Did a walk change the curve? Did sleep or stress seem to affect my numbers?
You do not need to understand everything on day one. Start small and use the data to learn one thing at a time.
Frequently Asked Questions
How long does each sensor last? Most OTC sensors last 10–14 days before needing to be replaced.
Does it hurt to put on or wear? Most people feel little to nothing during application — the inserter is designed to be quick. Day-to-day wear is generally comfortable, though you’ll feel the sensor if you bump it or sleep on that arm.
Can I use a CGM if I don’t have diabetes? Yes. OTC CGMs are specifically designed for people without diabetes who want to understand their metabolic health, manage weight, improve energy, or get ahead of blood sugar concerns.
How do I know if a CGM is actually working? The app will show a warming-up period of about an hour after application. After that, readings should be continuous. If something looks off, compare against a fingerstick reading or reach out to the manufacturer’s support.
Final Thoughts
Choosing your first CGM does not have to be complicated, but it helps to know what you want from it before you order.
Start with the basics:
- know your goal
- decide between OTC and prescription
- pay attention to the app
- understand the monthly cost
- think about how much guidance you want
The sensor gives you data. What you do with that data is where the real change happens.
If you want to compare beginner-friendly options, start with my full guide to the best CGM devices for weight loss. Two over-the-counter options you may see there are Stelo by Dexcom and Lingo by Abbott.
My biggest advice is this: do not just buy a CGM and hope the numbers make sense on their own. Go in with a clear reason for using it, then use what you learn to adjust your food, movement, and daily habits.
Have you tried a continuous glucose monitor yet, or are you still comparing options?
I’d love to know what your main goal is — weight loss, fewer cravings, better energy, blood sugar awareness, or something else.