--- title: "Non-invasive glucose monitors: what the FDA warns" description: "No smartwatch or smart ring is FDA-authorized to measure blood sugar on its own. Why a wrong number is risky, what a CGM is, and how to check a claim." canonical: https://glucosebench.com/non-invasive-glucose-monitors alternate_html: https://glucosebench.com/non-invasive-glucose-monitors language: en-US last_updated: 2026-09-27 type: guia --- # Blood sugar without a finger prick: the FDA warning on watches and rings 1. [Home](https://glucosebench.com/) 2. [Blood sugar basics](https://glucosebench.com/blood-sugar) 3. Blood sugar without a finger prick: the FDA warning on watches and rings A watch that reads blood sugar through the skin is an easy sell, and the FDA says dozens of companies make one. The agency's advice is short: don't buy it. By **GlucoseBench editorial team**Updated September 27, 2026 ![Blood sugar without a finger prick: the FDA warning on watches and rings](https://glucosebench.com/img/guia-non-invasive-glucose-monitors-640.webp) Short answer The FDA has not authorized, cleared, or approved any smartwatch or smart ring that measures or estimates blood glucose on its own, and in February 2024 it told people not to buy or use them. The danger is a wrong number: for people with diabetes, the FDA says an inaccurate reading can lead to the wrong dose of insulin or other glucose-lowering medicines, and too much of those can cause dangerously low blood sugar within hours. The closest thing to finger-free is a continuous glucose monitor (CGM), which uses a small sensor inserted under the skin; the FDA cleared the first over-the-counter CGM in March 2024, for adults who don't use insulin. For any gadget sold as a "glucometer without blood," ask whether the FDA has authorized it; if your care depends on accurate readings, the FDA says to talk to your provider about an FDA-authorized device. ## What the FDA warned about On February 21, 2024, the FDA warned consumers, patients, caregivers and health care providers about smartwatches and smart rings "that claim to measure blood glucose levels (blood sugar) without piercing the skin." Its central sentence: "The FDA has not authorized, cleared, or approved any smartwatch or smart ring that is intended to measure or estimate blood glucose values on its own." Sellers say these devices use non-invasive techniques. The FDA's description of them: "These smartwatches and smart rings do not directly test blood glucose levels." Dozens of companies make them under many brand names, and the warning covers every one that makes the claim, whatever the brand. When we read it on September 27, 2026, the page was unchanged (content current as of February 21, 2024). One distinction matters. A watch app that shows readings from an FDA-authorized device that does pierce the skin, such as a continuous glucose monitor (CGM), is a different thing, and the FDA says so on the same page. ## Why a wrong reading can hurt ### The wrong dose For people with diabetes, the FDA says inaccurate measurements can lead to "taking the wrong dose of insulin, sulfonylureas, or other medications that can rapidly lower blood glucose." ### A low that comes fast Too much of those medicines "can quickly lead to dangerously low glucose, leading to mental confusion, coma, or death within hours of the error." Our low blood sugar page has the 15-15 steps and when to call 911. ### Never reviewed The FDA says "the safety and effectiveness of these devices have not been reviewed by FDA," and that using them "could result in inaccurate measurements of blood glucose levels." ### What the FDA tells you to do Don't buy or use one. If your care depends on accurate readings, talk to your health care provider about an FDA-authorized device. If you think one gave you a wrong reading or caused a problem, report it through MedWatch, the FDA's voluntary reporting form. ## Watch, CGM or meter: how they compare Detail Watch or ring that claims to read glucose Continuous glucose monitor (CGM) Finger-stick meter Pierces the skin? Sellers say no Yes: a tiny sensor inserted under the skin, or a sensor implanted in the body Yes: a lancet prick, usually on a fingertip What it reads The FDA says it does not directly test blood glucose Glucose in the fluid between your cells, "very similar" to blood glucose, every few minutes Glucose in a small drop of blood on a test strip FDA status None authorized, cleared or approved to measure glucose on its own FDA-authorized models exist; the first over-the-counter one was cleared on March 5, 2024 Regulated as a medical device; the FDA says to use new strips authorized for sale in the United States Finger sticks Sold as needing none Fewer. Some models need one to calibrate, and a meter check is advised when a reading seems off, you change your insulin dose, or the CGM gives a warning One per check Who it's for No one, per the FDA Your doctor may recommend one if you need insulin (NIDDK); the over-the-counter model is for adults 18 and older who don't use insulin and don't have problematic hypoglycemia (FDA) People with diabetes, on their provider's advice (FDA) Sources, all read on September 27, 2026: FDA, "Do Not Use Smartwatches or Smart Rings to Measure Blood Glucose Levels: FDA Safety Communication" (February 21, 2024); FDA, "FDA Clears First Over-the-Counter Continuous Glucose Monitor" (March 5, 2024); FDA, "Blood Glucose Monitoring Devices" (content current as of November 14, 2024); NIDDK, "Continuous Glucose Monitoring" (last reviewed June 2023). We don't name device brands; your provider can tell you which one fits. ## The closest thing to needle-free, and its limits A CGM is what most people end up with when they want fewer finger sticks. Compared with a standard meter, the NIDDK lists better day-to-day glucose management, fewer low blood glucose emergencies and fewer finger sticks, plus alarms when glucose runs too low or too high. It isn't needle-free. The NIDDK says disposable sensors are replaced every 7 to 14 days depending on the model, while the FDA's announcement says the over-the-counter model's sensor is worn up to 15 days. The sticky patch can irritate some people's skin. Buying one without a prescription became possible in March 2024, when the FDA cleared the first over-the-counter CGM for adults 18 and older who don't use insulin, including people who manage diabetes with oral medicines and people without diabetes. It isn't meant for people with problematic hypoglycemia, since it isn't designed to alert them to it, and the FDA adds that users "should not make medical decisions based on the device's output without talking to their healthcare provider." A CGM also costs more than a standard meter, though the NIDDK says insurance or Medicare may cover it. ## Checking an FDA claim, on a gadget or a supplement The method is the one we use in our supplement reviews: find out what the FDA actually did. For devices, the FDA's Devices@FDA catalog lists cleared and approved medical devices, with the manufacturer and approval date. For watches and rings that claim to read glucose without piercing the skin, the FDA's warning already gives the answer: none had been authorized when it was last updated. Supplements are simpler still. "Under DSHEA, FDA does not have the authority to approve dietary supplements before they are marketed," the agency says, and "by law, FDA does not approve dietary supplements or their labeling." So a supplement page that shows a seal of FDA approval is wrong on its face. Two products reviewed here do it: Glycotide on its home page and GlycoFortin in its certifications image. An "FDA Registered Facility" seal, which Glyco Pulse shows, is a claim about a factory, not an approval of the product. Neither check tells you whether something works. What it does tell you is whether the seller is being straight with you, and a seller who invents an FDA status has answered that question already. ## Frequently asked questions **Is there a glucose monitor that doesn't use blood?** No smartwatch or smart ring is FDA-authorized to measure blood glucose on its own. A CGM comes closest: it reads glucose in the fluid between your cells instead of a drop of blood, but its sensor sits under the skin, and some models still need finger sticks. **Are smartwatches that measure blood sugar accurate?** The FDA says their safety and effectiveness haven't been reviewed, that they "do not directly test blood glucose levels," and that using them could give inaccurate readings. It tells people not to buy or use them. **Is a CGM non-invasive?** No. The NIDDK describes a tiny sensor inserted under the skin, often on the belly or arm, or a sensor implanted in the body. It needs fewer finger sticks than a standard meter, but not zero for every model. **Can I buy a CGM without a prescription?** Yes. The FDA cleared the first over-the-counter CGM in March 2024, for adults 18 and older who don't use insulin and don't have problematic hypoglycemia. The FDA says not to make medical decisions from its readings without talking to your provider. **What should I do if I've been using a smartwatch to check my blood sugar?** Stop relying on it, as the FDA advises. If your care depends on accurate numbers, ask your provider about an FDA-authorized device, and report a wrong reading or any harm through the FDA's MedWatch form. Never base an insulin or medicine dose on the watch's number. ## Related pages Blood sugar basics ### [Checking your blood sugar at home: the steps, the timing and a log worth keeping](https://glucosebench.com/check-blood-sugar-at-home) The CDC's steps for checking blood sugar at home: wash your hands with soap and warm water and dry them well, prick your finger with a lancet, put a small drop of blood… Read more Blood sugar basics ### [Low blood sugar (hypoglycemia): what to do in the first 15 minutes](https://glucosebench.com/low-blood-sugar) For most people with diabetes, blood sugar below 70 mg/dL is low, according to the CDC and the NIH; for people without diabetes, MedlinePlus says hypoglycemia is… Read more Blood sugar basics ### [Normal blood sugar levels, and why a diabetes target is a different number](https://glucosebench.com/blood-sugar-levels) For adults without diabetes, the CDC calls a fasting blood sugar of 99 mg/dL or below normal, 100 to 125 mg/dL prediabetes, and 126 mg/dL or above diabetes; an A1C below… Read more Updated September 27, 2026. 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