Direct-to-Consumer (DTC) Metabolic Monitoring

Introduction to Direct-to-Consumer (DTC) Metabolic Monitoring

Direct-to-consumer (DTC) metabolic monitoring means buying a glucose sensor yourself, without a prescription, and reading the results on your own phone. In the US the category is young. The FDA cleared the first over-the-counter (OTC) continuous glucose monitor, Dexcom's Stelo, on March 5, 2024, for adults who don't use insulin [1]. As of October 2026, the field is a short list of FDA-cleared sensors and apps, each with a narrower job than the prescription CGMs they grew out of.

Where the prescription line falls

A continuous glucose monitor (CGM) is a small sensor worn on the skin. It estimates glucose in interstitial fluid, the fluid between cells, and sends readings to a phone or reader. When the FDA cleared Stelo, it said the decision let people "purchase a CGM without the involvement of a health care provider" [1]. That is the line we use in this article. If a device needs a prescription, it isn't direct-to-consumer, however it's marketed.

The CGMs most people picture sit on the other side of that line. Dexcom tells people who are new to CGM that they need a prescription to start the Dexcom G7 15 Day [2]. Abbott's page for the FreeStyle Libre 3 system, which now uses the Libre 3 Plus sensor, asks readers to "ask your doctor for a prescription" [3]. The rest of this article is about the devices you can buy on your own.

The OTC devices cleared so far

Dexcom Stelo

Stelo is cleared as an OTC integrated CGM (iCGM) for people who don't use insulin [4]. "Integrated" is an FDA category for CGMs that meet set accuracy rules and can share data with other compatible devices. Here's what surprised us in the 510(k) summary: Stelo uses the same hardware as the prescription Dexcom G7 [4]. The differences are in firmware and software. Stelo is factory-calibrated, lasts up to 15 days plus a 12-hour grace period, and updates its app every 15 minutes [4]. The app gives no glucose or system alerts [4].

The first clearance covered adults 18 and older [4]. In June 2026 the FDA cleared a change that extends Stelo's labeling to people 2 and older who don't use insulin, with caregiver supervision for anyone under 18 [5].

Abbott Lingo

Abbott's Lingo was cleared on May 29, 2024, for adults 18 and older not on insulin [6]. Its biosensor is based on the FreeStyle Libre 2 sensor and is worn on the back of the upper arm for up to 14 days [6]. Like Stelo, it has no glucose alerts [6]. One detail in the filing shows how fast the prescription side moves. The device Abbott compared Lingo against was the FreeStyle Libre 2 Flash Glucose Monitoring System [6], and Abbott made the original Libre 2 sensor available only through September 30, 2025 [7]. Its prescription replacement is the Libre 2 Plus sensor [7].

Signos

Signos is software rather than a sensor. The FDA cleared the Signos Glucose Monitoring System on March 21, 2025, as an OTC phone app that receives data from an iCGM sensor [8]. Its 510(k) summary names Stelo as the comparison device and says the two use the same iCGM [8]. Signos's labeling adds a line the others don't carry: the glucose information "may be useful in helping users to maintain a healthy weight" [8].

Biolinq Shine

Biolinq Shine takes a different approach to sensing. Instead of a single wire under the skin, it uses an array of seven microsensors that sit in the upper layer of the dermis. It is worn on the inner forearm for up to five days, and it shows glucose as colored lights on the wearable itself rather than as numbers [9]. The FDA first authorized it on September 23, 2025, through the De Novo pathway for new device types, as a prescription device for adults 22 and older not on insulin [9]. A 510(k) cleared on September 18, 2026, added OTC use, backed by human factors testing and revised labeling [10]. We couldn't confirm from Biolinq or FDA records whether Shine is on sale to consumers yet.

One thing this list leaves out on purpose. In a February 2024 safety communication, the FDA warned that no smartwatch or smart ring that claims to measure glucose without piercing the skin is authorized, cleared or approved [11]. Those products are not part of this category.

Who the labels exclude

Every OTC label we read draws the same boundary. These devices are for people who don't use insulin, and the user "is not intended to take medical action based on the device output without consultation with a qualified healthcare professional" [4] [6] [8]. The FDA said Stelo is not for people with problematic hypoglycemia, because it isn't designed to alert them to low glucose [1]. Stelo's 2026 labeling also lists people on dialysis and people with a history of eating disorders among those it isn't for [5].

Biolinq's prescription labeling went further. It rules out use in type 1 diabetes, with any insulin, or with automated insulin delivery systems, and it warns that hydroxyurea causes inaccurate readings while acetaminophen may falsely raise them [9]. Whether an OTC sensor fits alongside someone's current treatment is a decision for their care team.

How accurate they are

Stelo and Lingo were both cleared under the FDA's iCGM rule, 21 CFR 862.1355 [4] [6]. One of that rule's accuracy tests requires the lower 95% confidence bound on the share of readings within 20% of a matching blood glucose value to exceed 87% [12]. Put plainly, the rule expects most readings to land close and allows a minority to miss by more than 20%. Biolinq Shine is classified under a different regulation, 21 CFR 862.1359, for glucose range monitoring systems [9].

The accuracy data came from people with diabetes, not from the healthy users these products also court. Stelo's clinical study enrolled adults with diabetes [4]. Abbott reused the Libre 2 clinical data for Lingo, arguing that people with diabetes have more variable glucose and are a worst case for sensor performance [6]. For how prescription sensors compare on MARD (mean absolute relative difference, the usual CGM accuracy summary), see our comparative accuracy and MARD analysis.

What the patent records show

A patent records what a company claimed as its invention. It doesn't show what's inside a product on the shelf. One record we read is US 11,963,796 B1, "Heterogeneous integration of silicon-fabricated solid microneedle sensors and CMOS circuitry," assigned to Biolinq Inc and granted on April 23, 2024 [13]. Its first claim covers a skin-worn sensing device: an array of microneedles, each with an addressable electrode, connected through a second layer that carries CMOS circuitry, the standard chip technology in most electronics [13]. That resembles the microsensor-array design in Shine's FDA summary [9]. Neither the patent nor the FDA summary says Shine uses it.

Paying for it

Direct-to-consumer usually means paying out of pocket. Medicare covers a CGM only when, among other requirements, the person is insulin-treated or has a documented history of problematic hypoglycemia [14]. The OTC labels exclude people on insulin, and Stelo's excludes problematic hypoglycemia too [1]. So the people these products are designed for generally sit outside Medicare's CGM criteria. We compare the OTC options in more depth in our article on the over-the-counter CGM market.