Wisner Baum LLP, a nationally recognized trial law firm, filed a class action lawsuit against Dexcom, Inc. in the United States District Court for the Southern District of California on behalf of consumers who purchased Dexcom G6 and G7 continuous glucose monitoring devices. The complaint alleges the medical devices were manufactured with unapproved materials, rendering them adulterated and misbranded under federal law, and that they failed to perform as advertised to consumers who relied on them for critical diabetes management decisions.
The case, Levens et al. v. Dexcom, Inc. (Case No. 3:25-cv-02565-BEN-BLM), was filed on September 29, 2025, by Wisner Baum class action attorney Behram V. Parekh.
Dexcom Devices Implicated in Class Action Allegations
The Dexcom G6 and G7 are continuous glucose monitoring (CGM) devices that use wearable sensors to track blood glucose levels in real time and send readings wirelessly to a smart device or receiver. They are designed to help people with diabetes manage their condition without fingersticks or scanning.
If a CGM fails to provide accurate readings, users may administer incorrect insulin doses or miss warnings of dangerously low glucose levels, potentially leading to hypoglycemic events that can result in seizures, loss of consciousness, or other serious medical emergencies.
FDA Warning Letter Reveals Unauthorized Manufacturing Changes
The proposed Dexcom class action allegations stem from a U.S. Food and Drug Administration (FDA) warning letter sent to the company on March 4, 2025. The FDA informed Dexcom that it had made unauthorized changes to a critical component used in manufacturing the G6 and G7 CGMs without obtaining the required premarket clearance. Specifically, Dexcom replaced a material used in a key sensor component with a different material without submitting a new premarket notification to the FDA as required by federal law.
Per the FDA warning letter, this material substitution caused the G6 and G7 sensors to be adulterated under Section 501(f)(1)(B) of the Federal Food, Drug, and Cosmetic Act because Dexcom did not have approved applications for premarket approval or investigational device exemptions in effect for the modified devices. The devices were also deemed misbranded under Section 502(o) of the Act because Dexcom introduced them into interstate commerce with major modifications without submitting required premarket notifications.
According to the complaint, Dexcom conducted two clinical studies demonstrating that sensors constructed with the unauthorized replacement material “had significantly greater variability than that of sensors constructed with” the FDA-approved material. The FDA also noted that data submitted by Dexcom showed “a significant difference in the standard deviation of glucose sensitivities between sensors built with" the two different materials, indicating "greater clinical performance variation” for sensors made with the unauthorized material.
The FDA stated in its warning letter that “the larger inaccuracies in [the replacement material]-coated sensors cause higher risks for users who rely on the sensors to dose insulin or make other diabetes treatment decisions.” The agency concluded that Dexcom had not demonstrated equivalency between the two materials and that the variability differences “could significantly affect the safety or effectiveness of the device,” requiring submission of a new premarket notification at least 90 days before commercial distribution of the modified devices.
Allegations of False and Misleading Marketing
The complaint alleges that Dexcom marketed and advertised the G6 and G7 CGMs as effective devices for monitoring blood glucose levels and warning consumers when their glucose levels became dangerously low or high. Dexcom represented that the products used “scientifically proven FDA cleared technology to effectively and accurately measure these levels and provide continuous monitoring of their blood glucose levels,” according to the complaint.
The complaint details Dexcom’s marketing claims regarding the G7 device. In a December 8, 2022, press release announcing FDA clearance of the G7, Dexcom claimed the device achieved “an overall MARD of 8.2%” and stated that “Dexcom G7 is the most accurate CGM cleared by the FDA.” MARD (Mean Absolute Relative Difference) is the most widely used metric for assessing the accuracy of continuous glucose monitoring devices. It quantifies how closely a CGM’s glucose readings match reference (typically laboratory or fingerstick) glucose values.
According to the class action complaint, Dexcom’s press release also touted the system's “predictive low alert that provides a 20-minute advance warning of potentially dangerous low glucose levels so users can act quickly to avoid a hypoglycemic event.”
On its website during the relevant time period, Dexcom marketed the G7 under the heading “Dexcom G7 offers industry-leading accuracy,” emphasizing that "having accurate readings is extremely important when you depend on readings to make diabetes management decisions.” The company further claimed that the “G7 is highly accurate when your glucose is low or high, and when it's changing quickly, giving you the confidence to make decisions when it's most important.”
However, class action attorneys say these representations were false, deceptive, and inaccurate because the devices sold to consumers were manufactured with unauthorized materials, which caused them to have significantly greater variability and reduced accuracy compared to the FDA-cleared versions.
Allegations in Dexcom Class Action Lawsuit
According to the complaint, “Defendants' G6 and G7 devices did not work as advertised and warranted because Plaintiff experienced incorrect readings from the Dexcom G6 and G7 devices and sensors when she would compare them to manually taken blood sugar readings.”
The complaint asserts seven causes of action on behalf of a nationwide class and California subclass. These include violations of the Magnuson-Moss Warranty Act, breach of express warranties, breach of the implied warranty of merchantability under the Uniform Commercial Code, and violations of several California consumer protection statutes.
The California-specific claims include alleged violations of the Consumer Legal Remedies Act (Civil Code § 1750 et seq.), the Unfair Competition Law (Business & Professions Code § 17200), the Song-Beverly Consumer Warranty Act, and the False Advertising Law (Business & Professions Code § 17500).
The complaint further alleges that Dexcom's representations violated the Consumer Legal Remedies Act by representing that “the Products had characteristics, uses, and benefits that they did not have” and by representing “that the Products were of a particular standard, quality and grade when they were of another.”
Under the Unfair Competition Law claims, the complaint alleges that Dexcom's conduct was “unfair, unlawful and fraudulent,” and that the company's business practices were unlawful because they violated California's false advertising statute and the Consumer Legal Remedies Act. The complaint further alleges that Dexcom's “acts and practices were fraudulent within the meaning of the UCL because they were likely to mislead the members of the public to whom they were directed” through advertisements, marketing materials, and product labeling that claimed the products “had properties and benefits they did not have.”
The proposed class includes all U.S. residents “who, within the applicable statute of limitations purchased a Dexcom G6 and/or G7 continuous glucose monitoring device and/or sensor that was made using sensor materials different than that approved by the FDA.” The California subclass consists of California residents who purchased the products primarily for personal, household, or family use.
According to class action attorneys, Dexcom sold consumers a product that should not have been available for sale in the market as an FDA-cleared device. The product was inferior in quality to the product as warranted, advertised, and marketed by Defendants, and did not perform as warranted, advertised, and marketed by Defendants, the complaint states.
As a result, plaintiffs “did not get the benefit of their bargains” and “were misled into purchasing Products that did not meet their expectations,” according to the complaint. Plaintiffs seek either full refunds of the purchase prices or recovery of the difference between the prices paid and what the products would have commanded if marketed truthfully.
The case is Levens et al. v. Dexcom, Inc., Case No. 3:25-cv-02565-BEN-BLM, U.S. District Court for the Southern District of California.
Individuals who purchased Dexcom G6 or G7 continuous glucose monitoring devices and experienced inaccurate readings can learn more about their legal rights by visiting our Dexcom lawsuit page.
