Wellness, Actually · April 16, 2026
Do continuous glucose monitors actually work for people without diabetes?
Continuous glucose monitors used to live in the pockets of people with type 1 diabetes. Now they live on the arms of triathletes, biohackers, and anyone who saw a wellness influencer hold one up to the camera. The question is whether any of that does anything for you.
What a CGM actually is, and who it was built for
A continuous glucose monitor is a small patch, usually worn on the back of the arm or the belly, with a thin wire that sits under the skin. It measures glucose in the interstitial fluid, which lags blood glucose by about 10 minutes, and sends the reading to an app.
For people with type 1 diabetes, this is a slam dunk. The randomized evidence is consistent: more time in the target range, lower A1C, less hypoglycemia, less anxiety for parents of kids with type 1. Some prescription CGMs even pair with insulin pumps, creating something that functions close to an artificial pancreas. For people with type 2 diabetes or prediabetes, there is also real evidence that CGM-driven feedback helps people eat in a way that keeps glucose steadier, and some studies suggest CGMs can delay progression from prediabetes to diabetes.
In 2024, the FDA approved an over-the-counter version. That is when this market exploded. Abbott and Dexcom sell them directly. You can buy a two-week sensor for about $50, stick it on, open the app, and watch a line move.
The "flat line at 90" myth
A lot of the influencer messaging around CGMs is built on a specific idea: that your glucose should be a flat line at 90 mg/dL all day, and that every "spike" is damage. That is not how human physiology works.
Normal blood glucose of about 90 mg/dL corresponds to roughly a teaspoon of sugar dissolved in your entire bloodstream. When you eat carbohydrates, glucose goes up. That is what carbohydrates are supposed to do. Your body then does its job: insulin moves glucose into cells and packs the rest into the liver as glycogen, so you have fuel later. Well-documented post-meal spikes to 160, 170, even 190 or 200 mg/dL can be entirely normal in healthy people, depending on what they ate. It does not mean you are insulin resistant or broken.
This matters because the word "spike" sounds bad. Pointy. Sharp. Influencers lean on that, then sell you a subscription.
What the evidence actually shows in non-diabetics
In people without diabetes, the outcome data for CGMs is thin. A meta-analysis of randomized trials comparing CGM users to non-users in non-diabetic populations found that CGM users did lower their mean blood glucose. That is a Hawthorne effect. If you watch a number, you push the number. Give someone a step counter and they take more steps. Give them a glucose reading and they skip the cookie.
The problem: there was no difference in BMI at the end of the trial. The number on the app moved. The outcome that arguably matters more did not.
There is also a correlation-versus-causation trap here. People who run higher on an oral glucose tolerance test are more likely to develop diabetes later. That could mean glucose excursions damage the pancreas over time. It could also just mean the test is identifying people who already have subclinical insulin resistance. If it is the second, lowering the spikes does not change your risk. It just tells you about your risk.
One tip for evaluating influencer claims in this space: Google whatever they are selling along with "randomized trial." You will get closer to the truth than whatever they are saying on camera.
Where CGMs might genuinely help non-diabetics
Interestingly, the strongest non-diabetic use case is not about preventing highs. It is about preventing lows in endurance athletes.
When you run, your body burns through the glucose in your blood fast, then taps liver glycogen, which typically runs out after 2 or 3 miles of sustained effort. After that you are in gluconeogenesis, breaking down protein and fat to make glucose. That is "hitting the wall." Studies in cyclists and runners show that CGM feedback helps athletes time carbohydrate intake to keep glucose from dropping below 70 mg/dL. The pro cycling peloton was using these to optimize fueling during stages of the Tour de France, and they got banned. When something gets banned in pro cycling, it is usually because it works.
Outside of endurance sports, there are narrower cases. If your fasting or non-fasted glucose came back unusually low on a standard blood panel and you want to see what is happening, a two-week sensor can answer that. If you feel dragged out at specific times of day and want data, maybe. But the question to ask is the same question you should ask about any expensive blood panel: what action will I take differently based on this information?
The real downsides
The device breaks the skin, so there is a theoretical infection risk. There is the cost, especially for monthly subscriptions bundled with AI "coaching" apps that promise answers the data cannot actually give.
And there is orthorexia nervosa. It is not yet in the DSM, but it is well described: an obsession with healthy eating that starts to interfere with daily life, relationships, and work. A related pattern around sleep trackers is called orthosomnia. CGMs feed directly into this. If you are the kind of person who could become fixated on producing a perfect flat line, do not put one on your arm.
The other real harm is food fear. People wear a CGM for two weeks, see their glucose hit 130 after a bowl of rice, and decide rice is poison. It is not. That is physiology working correctly.
Bottom line
For type 1 diabetes, type 2 diabetes, and prediabetes, CGMs are genuinely useful and in some cases transformative. For everyone else, the evidence that wearing one improves any hard health outcome is weak. The mean glucose drops a little while you are watching; the BMI does not budge. If you are curious, $50 for a two-week sensor is fine. A monthly subscription is not buying you much. And the goal of a flat line at 90 is not a real medical target, it is marketing.
I covered this in depth on Wellness, Actually — listen below.
Frequently asked questions
Is it bad if my blood sugar spikes after eating?
Not in a healthy person. When you eat carbohydrates, glucose is supposed to go up, and post-meal readings of 160, 170, even 190 or 200 mg/dL can be normal depending on what you ate. It does not mean you are insulin resistant. Your body then moves the excess glucose into cells and stores the rest as glycogen in the liver.
Should I wear a continuous glucose monitor if I don't have diabetes?
Probably not. A meta-analysis of randomized trials in non-diabetics showed CGM users lowered their mean blood glucose, but there was no difference in BMI at the end of the trial. The number moved because people were watching it, a Hawthorne effect, but the outcomes that matter did not change. If you are curious, a $50 two-week sensor is reasonable; a monthly subscription is not buying you much.
Do CGMs help with weight loss?
The randomized evidence does not support this. In trials of non-diabetics, people using CGMs did bring their average glucose down, but their BMI at the end of the study was no different from people who did not use a CGM. Lower numbers on the app did not translate into weight loss.
Why do endurance athletes wear continuous glucose monitors?
To avoid bonking. Liver glycogen typically runs out after 2 or 3 miles of sustained effort, after which the body has to make glucose from protein and fat. Studies in cyclists and runners show CGM feedback helps athletes time their carbohydrate intake to keep glucose from dropping below 70 mg/dL. The pro cycling peloton was using them for exactly this reason before they were banned.
What is a normal blood glucose range?
A normal fasting blood glucose is around 90 mg/dL, which corresponds to about a teaspoon of sugar dissolved in your entire bloodstream. A common target range over the course of a day is roughly 70 to 140 mg/dL, though healthy people can briefly go higher after meals. Glucose is kept in a narrow band because it is both necessary and, at high concentrations, toxic.
Can a CGM cause disordered eating?
It can contribute to it in susceptible people. Orthorexia nervosa, an obsession with healthy eating that interferes with daily life, is documented in the literature though not yet in the DSM. A related pattern around sleep trackers is called orthosomnia. If you are prone to fixating on producing a perfect number, a CGM is a bad idea, and the same goes for fearing normal foods like rice because they briefly raise your glucose.
Wellness, Actually Podcast
"What's the deal with continuous glucose monitors?" — Listen to the full episode, including the week's health news and listener Q&A.