Quick answer
If you do not have diabetes, a continuous glucose monitor (CGM) is now legal to buy without a prescription in the United States, and it will show you real patterns in how food, training, sleep, and stress move your blood sugar. What it will not reliably do, based on the research available right now, is tell you how to run faster or recover better. Treat the data as a curiosity tool for learning your own patterns, not as a performance dashboard or a diagnostic device.
By Mateo Rivera
Who This Matters Most For
This explainer is written for recreational and competitive athletes who do not have diabetes or prediabetes and who are curious about wearing a continuous glucose monitor to see what their body does during training, racing, and everyday life. It is less relevant to people managing diagnosed diabetes, who already have well-established, physician-guided reasons to use CGM technology, and it is not a substitute for medical advice. If you already have concerns about your blood sugar, fatigue patterns, or family history of diabetes, the right first step is a conversation with a physician, not a sensor purchase.
How a Continuous Glucose Monitor Actually Works
A CGM is a small, disposable sensor, usually about the size of a coin, that you apply to the back of the upper arm or the abdomen. A thin filament under the skin measures glucose in the interstitial fluid, the thin layer of fluid surrounding your cells, rather than drawing blood directly. That reading is converted into an estimated blood glucose value and sent by Bluetooth to a phone app every few minutes, building a continuous curve instead of the single-point snapshot you would get from a finger-stick test.
Because the sensor is measuring fluid around cells rather than blood itself, there is a natural lag of roughly five to fifteen minutes between what is happening in your bloodstream and what shows up on the app, and that lag tends to widen during exercise when blood flow and fluid shifts are more dramatic. Sensors are typically approved for wear periods of ten to fifteen days, after which you replace the whole unit. Most consumer systems on the market today, including the two discussed below, are built on sensor hardware originally engineered for people with diabetes, then paired with new software and marketing aimed at a general wellness audience.
The output is not one number but a curve: a rolling record of glucose values, the rate and direction of change, and summary statistics such as average glucose, glucose variability, and the percentage of time spent in a chosen range. Athletes who use CGM are typically looking at this curve around meals, workouts, and sleep to see, for example, whether a pre-run breakfast produces a sharp rise and fall, or whether a hard interval session is followed by several hours of unusually low readings.
What Is Actually FDA-Cleared for Non-Diabetic Use, and Since When
For most of CGM’s history since it reached the consumer market in the 2000s, every system sold in the United States required a prescription and was regulated with people who have diabetes as the intended user. That changed on March 5, 2024, when the U.S. Food and Drug Administration cleared the Dexcom Stelo Glucose Biosensor System as the first over-the-counter continuous glucose monitor available without a prescription. The FDA’s own announcement describes it as intended “for anyone 18 years and older who does not use insulin, such as individuals with diabetes treating their condition with oral medications, or those without diabetes who want to better understand how diet and exercise may impact blood sugar levels.” That sentence is the actual regulatory basis for marketing a CGM to healthy, non-diabetic exercisers, and it is worth reading closely because it authorizes general lifestyle curiosity, not athletic performance claims.
The clearance came with a specific limitation that matters for athletes: Stelo is explicitly not intended for anyone with problematic low blood sugar, because the device does not include low-glucose alerts the way prescription systems do. Dexcom sells Stelo directly to consumers, with a package of sensors listed at $99 on the company’s own site, positioned as HSA and FSA eligible, and marketed around phrases like “stabilize energy,” “improve focus,” and “build smarter habits” rather than clinical outcomes.
Abbott, the other major glucose-sensor manufacturer, has also moved into this space with its Lingo line of consumer biosensors, built on the same underlying FreeStyle Libre sensor technology the company has long sold under prescription for diabetes care. Abbott’s own public materials describe Lingo as a consumer wearable meant to help people connect glucose patterns to diet and exercise choices rather than to manage a diagnosed condition. As with Stelo, the intended user is a healthy adult who wants information, not a person relying on the device for insulin dosing or hypoglycemia safety.
The practical takeaway is that the regulatory door has opened. It is now legal and increasingly common for a non-diabetic runner, cyclist, or lifter to strap on the same style of sensor a person with type 1 diabetes might use for insulin decisions. What has not changed nearly as fast is the evidence base showing what a healthy athlete should actually do with that data once it starts arriving every five minutes.
Evidence strength: what CGM claims actually hold up
Strong
Moderate
Limited
Based on the peer-reviewed literature and expert reviews cited in the References section below. Bar length is a qualitative summary, not a statistical measure.
What the Research Does and Doesn’t Show
A 2022 review in the journal Sensors by Holzer, Bloch, and Brinkmann laid out the case for CGM’s potential in healthy adults, noting that the technology “can be used for early detection of abnormal glucose regulation” and that learning how food and physical activity affect an individual’s glucose responses “can be helpful in improving nutritional and/or physical activity behavior.” The authors were optimistic about the direction of the field, but they also flagged that more research was still needed to properly interpret the data and combine it with other wearable measurements before firm recommendations could be made for wellness or sports use.
A separate 2023 review in the Journal of Diabetes Science and Technology by Klonoff and colleagues mapped out who is actually buying CGMs without a diabetes diagnosis. The authors grouped users into four categories: people with metabolic conditions on the path toward diabetes, people with other metabolic conditions unrelated to insulin, health-conscious consumers, and competitive athletes. They described the trend as CGM technology extending beyond diabetes management into “prevention, performance enhancement, and behavior modification,” while also noting that the field is still working out which glycemic patterns actually predict anything useful in people who do not have a glucose-regulation disorder.
The most directly relevant, and most sobering, source is a 2025 report from the Gatorade Sports Science Institute written by exercise physiologist Michael Riddell and colleagues, titled “Continuous Glucose Monitoring Use in Athletes Without Diabetes.” It is worth quoting at length because it is one of the few sources that directly addresses what “normal” looks like in trained athletes. The authors note that healthy, non-athletic adults spend about 96% of their time with glucose between 70 and 140 mg/dL, but elite athletes routinely spend 10 to 20% of their waking hours above 140 mg/dL and another 5 to 7% below 70 mg/dL, largely as a normal consequence of training stress, liver glucose output, and fueling strategy. Their conclusion is direct: this variability “appears physiologically normal” and is “not disadvantageous.” The same report states plainly that “the ideal CGM glucose range for healthy athletes is currently unclear,” which means anyone selling a specific target range to a non-diabetic athlete right now is making a claim the science does not yet support.
On the accuracy side, a 2024 study in the European Journal of Applied Physiology by Matzka, Ørtenblad, Lenk, and Sperlich tested a consumer CGM against finger-stick blood readings in young, non-diabetic adults during an intense leg-squat session under different carbohydrate conditions. The sensor performed with what the authors called satisfactory group-level accuracy, but individual results varied substantially, and error grid analysis showed only 50.5% to 64.3% of readings fell in the most clinically reliable zone, with the biggest gaps opening up right after exercise, exactly when an athlete is most likely to be checking the app for recovery cues. The researchers’ own summary is blunt: CGM “could aid non-diabetic athletes by tracking glucose fluctuations due to diet and exercise,” but “the application in sports nutrition is not yet validated.”
Put together, these sources paint a consistent picture. The technology reliably shows you a curve. What that curve means for a specific healthy athlete’s training, fueling, or recovery decisions is still an open research question, not a settled one, and the current honest answer to “will this make me faster” is that nobody has proven it will.
The numbers behind the story
Sources: FDA (2024); Gatorade Sports Science Institute, Riddell et al. (2025); Matzka et al., European Journal of Applied Physiology (2024). Full citations below.
How to Read a Glucose Curve Without Diagnosing Yourself
The single biggest risk of putting a medical-grade sensor on a healthy person is not the sensor itself, it is the temptation to treat every wiggle in the line as a problem. A rise to 160 or 170 mg/dL after a big bowl of pasta before a long run is a normal, expected response in a person without diabetes, not a warning sign. So is a dip below 70 mg/dL an hour into a hard training session, particularly if you started the workout in a fasted or carbohydrate-depleted state. As the Gatorade Sports Science Institute report notes, these swings are common in trained athletes specifically because muscle and liver glucose handling ramps up sharply during exercise, and that is a sign of a metabolically active body, not a broken one.
A more useful way to look at the data is trend over time rather than any single spike. Ask whether your overnight glucose is unusually low or flat after a heavy training block, which some coaches use as a rough proxy for inadequate fueling or incomplete recovery, or whether a particular pre-workout snack consistently produces a sharp rise followed by a rapid crash partway through your session, which might be worth adjusting regardless of the absolute numbers involved. These are pattern observations, not diagnoses, and they are best treated as hypotheses to test through your own training log rather than facts about your metabolic health.
If you notice a pattern that looks genuinely unusual, such as glucose values that stay elevated for hours after eating even at rest, or very frequent low readings unrelated to exercise or fasting, that is information worth bringing to a physician for a real diagnostic workup, not something to self-manage based on an app. A consumer CGM is a wellness device, not a diagnostic one, and its own labeling says as much.
Cost and Practicality
Dexcom lists Stelo sensors at $99 directly through its own site, a figure that is HSA and FSA eligible, and each sensor is worn for roughly two weeks before replacement, which puts ongoing use in the range of a moderate monthly subscription rather than a one-time purchase. Abbott’s Lingo line is positioned similarly, sold directly to consumers rather than through insurance, since neither product is intended to treat a diagnosed condition. Compared with a finger-stick glucose meter, which costs very little per test but only gives you one data point at a time, a CGM trades a higher price for continuous data; compared with prescription CGM systems used for diabetes management, the non-prescription versions are generally cheaper but also strip out safety features like low-glucose alarms that a person with diabetes would need.
Practicality matters as much as price. The sensor sits on the skin for the full wear period, which means showering, swimming, sweating heavily, and contact sports all have to be planned around it, and some athletes report skin irritation or the sensor catching on clothing or equipment during technical training. The data itself also requires a smartphone and a working Bluetooth connection nearby, which is a real limitation during long outdoor efforts, remote trail runs, or team sports where the phone is not on your body.
CGM Compared With Other Athlete Monitoring Tools
Non-diabetic athletes already have several ways to track their bodies, and it is worth seeing where glucose data fits next to the more established options.
Pricing reflects current publicly listed rates from each manufacturer’s own site and is subject to change; see References for sources.
Checklist: Questions to Ask Before Trying a CGM
- Do I have any personal or family history of diabetes, prediabetes, or blood-sugar concerns that I should discuss with a physician before, not after, I start wearing a sensor?
- Am I buying this to learn a pattern over two to four weeks, or am I expecting it to hand me a training plan on its own?
- Can I commit to the wear schedule, including keeping the sensor dry enough and secure enough for my sport?
- Do I understand that a single high or low reading is not a diagnosis, and that I should not change medication, insulin, or medical treatment based on this device?
- Have I budgeted for ongoing sensor replacement, not just the first purchase?
- Will I actually look at the trend data, or will this become another app notification I ignore after a week?
- If I see something that looks abnormal and persistent, do I have a plan to follow up with a doctor rather than trying to self-interpret it?
A Worked Example: Priya’s Half-Marathon Block
Priya is a 34-year-old recreational runner training for her third half marathon. She has no diabetes diagnosis, no family history of it, and a recent annual checkup with normal fasting labs. She buys an over-the-counter CGM out of curiosity after a friend mentions it, planning to wear two sensors back to back, about four weeks of data, during her peak training block.
In week one, she notices her glucose climbs to about 165 mg/dL after her usual pre-run bagel and honey, then drops to around 78 mg/dL forty minutes into her run, coinciding with a stretch where she feels unusually flat. Read in isolation, that dip might look alarming. Read as a pattern, it lines up with a known, well-described phenomenon called reactive hypoglycemia, where a large, fast-digesting carbohydrate load triggers a bigger insulin response than a mixed meal would, and the resulting glucose drop happens to land mid-workout. Priya does not have a medical problem; she has a fueling-timing problem, and one that a sports dietitian could have flagged without a sensor at all, simply by asking about her pre-run routine.
She experiments by swapping the bagel and honey for a smaller carbohydrate portion with some protein, eaten a bit earlier, and the sharp rise-and-crash pattern softens over her next several runs. Whether this measurably improved her actual half-marathon time is impossible for her, or for a single case study, to know. What changed is that she feels less midrun fatigue on that particular fueling plan, which she could plausibly have discovered through trial and error and a training log, just more slowly. That is a realistic, honest picture of what CGM data can offer a healthy athlete right now: a faster route to noticing a pattern you might otherwise have found anyway, not a guaranteed performance edge.
By week four, Priya stops looking at the app daily. The novelty has worn off, the big pattern she was going to find has been found, and she decides not to renew the sensor subscription for her next training cycle. That, too, is a common and reasonable outcome.
Common Mistakes Athletes Make With Glucose Data
What Sports Dietitians and Endocrinologists Say
The clearest expert voice on this specific question comes from the sports-science side rather than general endocrinology. Michael Riddell, an exercise physiologist whose research group authored the Gatorade Sports Science Institute’s 2025 report on CGM in athletes without diabetes, and his co-authors frame the technology’s realistic near-term value narrowly: helping athletes personalize nutrition timing, spot reactive drops after certain pre-workout meals, and notice unusually low overnight readings that might flag inadequate fueling during a heavy training block. Their language is measured rather than promotional, and they are explicit that “the ideal CGM glucose range for healthy athletes is currently unclear.”
Endocrinology-side researchers reviewing the broader non-diabetic CGM trend, including Klonoff and colleagues in their 2023 review, describe the field as expanding quickly in commercial terms while the clinical understanding of what the resulting data means in healthy people still lags behind. Neither group is arguing that non-diabetic athletes should avoid CGM. Both are describing a genuine gap between what the sensors can measure and what anyone can currently tell you to do about it.
The practical synthesis, consistent across these sources, is that CGM is a reasonable tool for self-experimentation and curiosity for a healthy athlete who wants it, and a poor substitute for individualized guidance from a sports dietitian or physician when something about the data looks genuinely concerning rather than merely unfamiliar.
Safety and scope
This article is educational and is not medical advice. Normal glucose fluctuation in a healthy, non-diabetic person is common and is not, by itself, evidence of a medical problem. If you have any personal concern about your blood sugar, a family history of diabetes, or symptoms such as persistent fatigue, excessive thirst, or unexplained weight change, talk with a physician before starting to use a CGM and before making any changes based on its readings. A consumer CGM does not diagnose diabetes, prediabetes, or any other condition, and it should never replace clinical blood testing or a doctor’s evaluation.
Key Takeaways
- The FDA cleared the first over-the-counter CGM, Dexcom Stelo, in March 2024 for adults not on insulin, explicitly including people without diabetes who want to understand how diet and exercise affect their glucose.
- Abbott’s Lingo line offers a similar consumer-facing option built on the company’s established glucose-sensor technology.
- Elite, non-diabetic athletes normally spend meaningful portions of the day outside the 70-140 mg/dL range that describes typical non-athletes, and current research describes this as normal rather than harmful.
- Peer-reviewed evidence supports CGM as a way to observe personal patterns, but does not yet support specific glucose targets or proven performance gains for healthy athletes.
- Sensor accuracy is weakest right around and after exercise, exactly when athletes are most likely to check the data for recovery cues.
- Persistent or unusual patterns deserve a conversation with a physician, not a self-diagnosis from an app.
Frequently Asked Questions
Do I need a prescription to buy a CGM if I don’t have diabetes?
No. Since the FDA’s March 2024 clearance of Dexcom Stelo, over-the-counter CGMs are legally available in the United States to adults 18 and older who do not use insulin, which includes healthy people without diabetes.
Is a non-prescription CGM the same device as one used for diabetes management?
It is built on related sensor technology, but the non-prescription versions typically lack features like low-glucose alarms that people managing diabetes rely on for safety, and they are labeled for general wellness use rather than medical treatment decisions.
Will wearing a CGM make me a faster runner or cyclist?
There is no strong published evidence that CGM use directly improves performance in athletes without diabetes. It can help you notice fueling patterns that might indirectly support better training sessions, but no controlled research currently shows a measurable performance benefit from the device itself.
A meal spiked my glucose to 160 mg/dL. Does that mean something is wrong with me?
Not by itself. Post-meal rises into this range are common in people without diabetes, especially after higher-carbohydrate meals, and are not evidence of a metabolic disorder on their own. Persistent, unusually high, or unusually prolonged elevations are worth discussing with a doctor.
How accurate are these sensors during exercise?
Research on consumer CGMs during exercise, including a 2024 study published in the European Journal of Applied Physiology, found reasonable group-level accuracy but notable individual variability, with the largest gaps between sensor readings and actual blood glucose showing up during and immediately after intense exercise.
How much does an over-the-counter CGM cost?
Dexcom lists its Stelo sensors at $99 per pack directly on its own site, with each sensor worn for roughly two weeks, making it eligible for HSA or FSA spending. Ongoing use functions more like a recurring cost than a single purchase.
What glucose range should I aim for as a healthy athlete?
Current sports-science reviews, including a 2025 report from the Gatorade Sports Science Institute, state directly that the ideal glucose range for healthy athletes is not yet established. Ranges published for people with diabetes are not necessarily appropriate targets for someone without the condition.
Should I talk to a doctor before starting a CGM even if I feel fine?
If you have any family history of diabetes, prior concerns about blood sugar, or symptoms like unusual fatigue or thirst, yes, it is worth a conversation first. If none of that applies, a CGM is generally considered a low-risk wellness device, but the data should still be interpreted with caution rather than treated as a diagnosis.
References
- U.S. Food and Drug Administration. “FDA Clears First Over-the-Counter Continuous Glucose Monitor.” Press Announcement, March 5, 2024. fda.gov
- Dexcom. Stelo Glucose Biosensor System, product and pricing information. stelo.com
- Holzer R, Bloch W, Brinkmann C. “Continuous Glucose Monitoring in Healthy Adults: Possible Applications in Health Care, Wellness, and Sports.” Sensors, 2022; 22(5):2030. doi.org/10.3390/s22052030
- Klonoff DC, Nguyen KT, Xu NY, Gutierrez A, Espinoza JC, Vidmar AP. “Use of Continuous Glucose Monitors by People Without Diabetes: An Idea Whose Time Has Come?” Journal of Diabetes Science and Technology, 2023;17(6). doi.org/10.1177/19322968221110830
- Matzka M, Ørtenblad N, Lenk M, Sperlich B. “Accuracy of a Continuous Glucose Monitoring System Applied Before, During, and After an Intense Leg-Squat Session with Low- and High-Carbohydrate Availability in Young Adults Without Diabetes.” European Journal of Applied Physiology, 2024. doi.org/10.1007/s00421-024-05557-5
- Riddell MC, Skroce K, Turner LV, Zignoli A, Zisser HC, Hinkley JM. “Continuous Glucose Monitoring Use in Athletes Without Diabetes.” Sports Science Exchange #263, Gatorade Sports Science Institute, May 2025. gssiweb.org
- WHOOP. Membership pricing and device tiers. whoop.com
- Oura. Ring and membership pricing. ouraring.com
- Wikipedia. “Abbott Laboratories,” section on Lingo consumer biowearables. en.wikipedia.org
