My Experience with Levels (Continuous Glucose Monitoring)

September 2021 ยท 7 minute read


I used the Levels Health program for a 4-week period and I found a few benefits, but unfortunately I discovered several catastrophic problems with the program (and the sensors they use) that caused me to doubt the value that it can bring for most people.

Knowing that Levels recommends of a target fasting glucose range of 78.5 mg/dL +/- 8.2%, I don’t see how I can possibly justify any trust in the Levels program when I observed a measurement error of 19.4% compared to a lab blood draw. This is larger than the entire span of their recommended fasting range.

Over the past few years, a few services have popped up around the world which provide continuous glucose monitoring to the masses. Historically, continuous glucose monitors have only been available to patients with diabetes. Services such as Levels and Supersapiens allow pretty much anyone to get access to continuous glucose monitors by facilitating the prescription without requiring a face-to-face meeting with a doctor.

How it Works

Levels forms relationships with physicians and pharmacies on a state-by-state basis. When a user signs up for their service, Levels asks the user to fill out a questionnaire. Levels then facilitates whatever communication is necessary with their in-state physicians and pharmacies to get the user a prescription for a continuous glucose monitor. My monitors lasted 2 weeks each. The user connects the monitor manufacturer app to the Levels service to allow sharing of their health data, and Levels guides the user through the experience of the program.

Levels provided me with LibreLink sensors.


The program is not cheap. It costs a few hundred bucks to sign up ($400 for me) and an additional couple hundred to continue the program ($200/mo at the time that I stopped). Compared to physician guidance and lab tests, however, it’s inexpensive… but it won’t be covered by insurance, since you probably don’t have a history of diabetes (or else you wouldn’t be going through Levels, you’d already be treated by your regular doctor…).

I paid for the program with my HSA account. I enjoy using services such as Levels and InsideTracker to learn more about my own body and to try to optimize my health.

Levels “Goals”

Levels states a few specific goal ranges for blood glucose levels at points throughout the day. As of August 2021, when I participated in their program, these points included:

My Experience

There were three major hiccups that I experienced during this whole process.

First, I was approved in the program, but something happened where I was never shipped my intro box. I contacted Levels 4 weeks after they charged me, and they sent out my introductory kit immediately.

Second, the first sensor I applied to myself was a dud. Sensors have to normalize for 8 hours after you apply them, so it took an overnight period before I concluded that something was wrong. Once again, I contacted Levels, and they sent out a replacement sensor immediately.

Third, and this is the biggest issue, is that I cross-referenced their sensor data with a blood draw, and found it to be wildly inaccurate. I used to work as an engineer for medical device companies, so I’m well aware of the caveats that go into sensor data… but the sensors that Levels provided had errors that were greater than the entire ranges of their recommended goals. Putting this bluntly, my fasting glucose according to a blood draw was 77 mg/dL, and the sensor that Levels gave me recorded 92 mg/dL at the exact time of the blood draw. That’s a difference of 15 mg/dL, which is larger than the entire recommended range they give for fasting glucose levels.


My average glucose measurements over my 4-week engagement with Levels were:

If you look at the numbers above, can you guess when I had my blood draw to compare the Levels sensor measurement with a more-accurate metric? If you guessed week 3 or 4, you nailed it!

The difference in my week 1-2 vs. week 3-4 average was 13.5 mg/dL, which is very close to the observed 15 mg/dL discrepancy in fasting glucose that I verified via a lab blood draw in week 4

Suffice to say, I think my sensor in weeks 3-4 was garbage. So that means that 2 of 3 sensors I was given were worthless when it comes to gaining actionable insights.

Things I liked

During the first two weeks of the program, I thought Levels was great. I had immediate, actionable feedback about which foods would cause my blood sugar to spike. Of all things, hummus was the most unexpected culprit of unexpected spikes… who would’ve thought that, for me, ground-up sesame seeds and garbanzo beans would spike my blood sugar? I would never have guessed that. Also, dairy products caused huge spikes in my blood sugar - I verified this across yogurt, full-fat milk lattes, and cheeses. Other things that I think of as “healthy” that caused big spikes: breakfast burritos, peanut-butter-toast, bananas, apples.

I learned that pizza is just about the worst thing that I eat on a semi-regular basis (maybe once per week), when it comes to spiking my blood sugar. the combo of carbs and dairy sends my glucose levels through the roof (relative to my baseline).

I should eat more potatoes - they don’t spike my blood sugar very much at all.

I was reassured by the program that I am far from becoming diabetic anytime soon, but it’s still very useful to know which foods will be bad for me to continue eating regularly in the long term.

It was also cool to see in real-time, in my own body, the effects of exercise windows on the body’s ability to process carbohydrate. I did a few long runs while I was wearing my sensors, and during those long runs I ate hundreds of grams of simple carbs with zero obvious effect on my blood sugar. For me, the 30-minute period after stopping exercise is when I should ingest any recovery meals… after 30 minutes, that recovery drink will spike my blood sugar.

Things I disliked

The biggest thing that bothered me, hands-down, was the +19.4% measurement error in my fasting glucose that I found via a direct comparison of the Librelink sensor with a blood measurement from my doctor’s office.

Knowing that Levels recommends of a target fasting glucose range of 78.5 mg/dL +/- 8.2%, I don’t see how I can possibly justify any trust in the Levels program when I observed a measurement error of 19.4% compared to a lab blood draw. This is larger than the entire span of their recommended fasting range.

Another minor thing - the sensors hurt. I felt a dull, aching pain for the few days after applying a new one. It makes sense, because they stick a needle into your muscle.


I think there’s promise for continuous glucose monitoring, but in my experience, the Levels program needs some serious improvements. The Librelink sensor is, in my opinion, absolute garbage. It’s not worth anything, much less $400 + $200/mo. 1 of 3 sensors was dead on arrival, and another had a continuous measurement error of nearly 20%, which is more than the differences anyone would measure by altering their lifestyle.

So, no, I would not recommend Levels unless they switch out the Librelink sensor for something more accurate. They should also be more transparent about the inaccuracies that they’re aware of… it’s hard for me to believe that they aren’t aware of these issues.

Thanks for reading!