Not reliably with a consumer smartwatch or smart ring. In the United States, the FDA says no watch or ring that measures or estimates glucose on its own has been authorized, cleared, or approved, and advises consumers not to use one for glucose measurement. Research into measuring glucose through intact skin is real, but it has not yet established a consumer-ready alternative for treatment decisions.
Can a smartwatch measure blood sugar without pricking your finger?
No smartwatch or smart ring that measures or estimates glucose on its own is an FDA-authorized glucose monitor in the United States. In a safety communication issued February 21, 2024, the U.S. Food and Drug Administration said: “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.” The agency advises consumers not to buy or use such watches or rings to measure glucose. Read the FDA safety communication.
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This warning concerns devices that claim to measure glucose independently, not smart devices that display readings from a separate, authorized glucose-monitoring system. A watch or phone can serve as a screen for readings transmitted by a compatible monitor; that does not mean the watch or phone is measuring glucose through the skin.
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How does optical glucose monitoring through skin work?
Noninvasive monitoring aims to estimate glucose without a blood drop or a sensor inserted through the skin. Optical spectroscopy shines light into or onto tissue and analyzes the signal that returns. Researchers study several approaches, including near-infrared and mid-infrared spectroscopy and Raman spectroscopy. Mid-infrared light can target molecular-vibration bands associated with glucose.
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Skin contains interstitial fluid, the fluid surrounding cells, where glucose is present. But a device must distinguish glucose-related signals from other tissue signals and convert them into a dependable estimate of blood glucose. The signal can be affected by skin differences, movement, device stability, and substances on the skin, among other measurement conditions. Detecting a signal associated with glucose is not by itself proof that a device can deliver accurate readings suitable for care.
Are noninvasive glucose monitors real yet?
They are real as research approaches, but the evidence does not establish an FDA-authorized consumer watch or ring that measures glucose through intact skin. The American Diabetes Association’s 2023 laboratory guideline says no noninvasive glucose device is FDA-approved for clinical measurements in the United States. See the ADA guideline.
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What a 2025 prototype study found
A 2025 prospective, single-center clinical evaluation tested DiaMonTech’s D-Base mid-infrared spectroscopy prototype in 36 participants. The system used a quantum-cascade laser to excite glucose in the skin and photothermal deflection to detect the resulting signal. Across two evaluation sessions using different amounts of calibration data, the study’s best algorithm reported mean absolute relative differences of 20.7% and 19.6%. These are results for that prototype and study—not a general performance estimate for all noninvasive methods, and not evidence that a consumer device is authorized or suitable for treatment decisions. Read the study in Communications Medicine.
The paper also discusses device instability, differences in skin, movement artifacts, and skin-care products as factors associated with signal instability or inaccuracies. It describes a handheld D-Pocket as under development and a wearable form as a future concept; the study does not establish either as an authorized consumer product. It also does not provide a broad, controlled comparison of commercially available noninvasive monitors.
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What can you use instead?
Available monitoring options differ in how they collect glucose data and what they require. The comparison below distinguishes intact-skin research from established ways of measuring glucose.
| Method | How it measures | Monitoring pattern | Practical requirements and status |
|---|---|---|---|
| Finger-stick meter | Tests a drop of blood obtained by pricking a fingertip. | Spot checks when the user tests. | Requires a compatible meter and test strips. It is not a way to measure glucose through intact skin. |
| Continuous glucose monitor (CGM) | Measures glucose using a sensor inserted under the skin. | Provides ongoing readings, trends, and, depending on the system, alerts. | Requirements vary by system. The sensor penetrates the skin, so a CGM is not noninvasive. |
| Noninvasive optical research device | Analyzes light interacting with tissue to estimate glucose-related signals. | Depends on the research system; no general consumer monitoring pattern is established by the cited evidence. | Research prototypes are not interchangeable with authorized devices for clinical or treatment use. |
An FDA-authorized CGM example: Eversense E3
Eversense E3 illustrates the distinction between a minimally invasive CGM and a through-skin optical device. The FDA describes it as a prescription system for adults with diabetes. A doctor implants its sensor under the skin, and glucose values are transmitted to a smart device every five minutes. The FDA page lists an approval date of March 29, 2023, wear of up to 180 days, and fingertip blood calibration when prompted. It is not a device that measures glucose through intact skin. See the FDA’s Eversense E3 approval information.
Why an inaccurate reading can be dangerous
The FDA warns that inaccurate glucose readings can lead to diabetes-management errors, including taking too much insulin or another glucose-lowering medication and developing dangerously low blood glucose. Do not use an unauthorized watch or ring’s estimate to make medication or treatment decisions. If your care depends on accurate glucose readings, talk with a health care provider about an FDA-authorized device appropriate for your needs. FDA guidance and consumer recommendations.
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