How a 2018 De Novo Let Dexcom Put a Glucose Monitor on a Toddler

Sometime this summer a parent will pick a glucose sensor off a pharmacy shelf, near the reading glasses and the pregnancy tests, and stick it on the arm of a two-year-old. No prescription. No clinic visit. That is the part of this clearance the coverage is leading with, and it is the right hook. The part worth studying is that Dexcom could pull it off cheaply, and the reason traces back to a regulatory decision the company made eight years ago.

What Dexcom actually cleared

This month the FDA cleared the Dexcom Stelo Glucose Biosensor System for children as young as two who do not use insulin, the first time a continuous glucose monitor has been sold over the counter to anyone under eighteen. Stelo has been available without a prescription to adults since March 2024. The hardware did not change. The sensor still reads glucose every fifteen minutes, lasts up to fifteen days, and pairs with a phone. What changed is the labeled population, and the careful fence around it. Stelo is not for people who take insulin, not for anyone with a history of dangerous low blood sugar, not for dialysis patients, and it does not alert you to a crisis. The FDA was explicit that it is a supplement to medical care, not a replacement. That fence is not fine print. It is the whole reason a clinical-grade sensor gets to sit on a retail shelf.

The decision that made it cheap

Back in 2018, Dexcom's G6 became the first integrated continuous glucose monitor the FDA ever authorized, through a De Novo. A De Novo is what you file when there is no predicate to point at, when nothing like your device has been cleared before. Founders treat that as a punishment, a sentence to extra time and extra evidence. I think that is exactly backward. When the FDA routes you to a De Novo, it is telling you it considers your device moderate risk and inside the bounds it will accept. And if you get through, you do not just get cleared. You write the classification. You become the predicate every later entrant has to match, including your own next product.

I watched this from the inside at Galen Robotics. Our pre-submission routed us to De Novo, we drafted the proposed regulation, and the FDA took our language almost word for word in a couple of days. We did not squeak through someone else's standard. We set it. That is what Dexcom did for the entire CGM category in 2018, and it is why this week's pediatric clearance was a label expansion riding on real estate the company already owned, not a fresh fight.

Where founders should point the regulatory dollars

If you are building a device with no obvious predicate, a novel diagnostic, a new class of wearable, a piece of software that does something the FDA has not classified yet, a De Novo is the asset, not the detour. Every expansion afterward, a new age group, an over-the-counter version, an added claim, becomes a cleaner, cheaper filing against the standard you authored. Dexcom has now run that play twice off one 2018 decision: first to over-the-counter for adults, now to children. The exclusions do the same work in the other direction. By drawing the fence to leave out insulin users, Dexcom kept Stelo out of the high-risk envelope where dosing decisions live, which is what keeps it over the counter at all. The population you deliberately leave out is as much a product decision as the one you chase. Spend the regulatory budget early, on the framing and the standard, not late, on defending a sloppy one.

Dave Saunders is the founder of Base Reality Group and a Fractional CPO for hard-tech founders. He was a founder and operator at Galen Robotics, where the surgical-robotics platform earned FDA De Novo authorization in 2023, and he managed a 35-patent portfolio licensed from Johns Hopkins. He wrote Founders Who Finish and publishes The Build. More about Dave →