Enso for Migraine
Device Facts
| Record ID | K254216 |
|---|---|
| Device Name | Enso for Migraine |
| Applicant | Hinge Health, Inc. |
| Product Code | PCC · Neurology |
| Decision Date | Apr 16, 2026 |
| Decision | SESE |
| Submission Type | Traditional |
| Regulation | 21 CFR 882.5891 |
| Device Class | Class 2 |
| Attributes | Therapeutic |
Indications for Use
Enso for Migraine is indicated in patients 18 years of age or older for the acute treatment of migraine with or without aura and the preventative treatment of migraine. Enso for Migraine is for patients diagnosed with migraine by a physician.
Device Story
Enso for Migraine is a wearable, app-controlled TENS device for migraine treatment. User applies hydrogel pad to forehead; attaches neurostimulator via magnets. Device delivers transcutaneous electrical stimulation to excite nerves in head, creating neuromodulation effect to reduce migraine frequency/severity. System includes neurostimulator, gel pads, charging dock, and mobile app. User operates device via app to initiate sessions and adjust settings. Healthcare provider diagnosis required prior to use. Benefits include non-pharmacological migraine management. Device is intended for OTC use.
Clinical Evidence
No clinical performance testing conducted. Safety and effectiveness established via bench testing (therapeutic performance, gel pad/skin interface) and human factors study. Clinical effectiveness supported by analysis of published clinical literature for the predicate device.
Technological Characteristics
TENS device; acrylic hydrogel electrodes; rechargeable LiPo battery; Bluetooth connectivity. Single-channel output. Asymmetric biphasic, rectangular, fully compensated waveform. Compliant with IEC 60601 and ISO 10993. Wireless control via mobile app. Form factor: 42x42x11 mm, 13.5g.
Indications for Use
Indicated for patients 18+ years old for acute treatment of migraine with or without aura and preventative treatment of migraine. Patients must be diagnosed with migraine by a physician.
Regulatory Classification
Identification
A transcutaneous electrical nerve stimulator to treat headache is a device used to apply an electrical current to a patient's cranium through electrodes placed on the skin.
Special Controls
*Classification.* Class II (special controls). The special controls for this device are:(1) The patient-contacting components of the device must be demonstrated to be biocompatible. (2) Appropriate analysis/testing must validate electromagnetic compatibility and electrical, mechanical, and thermal safety. (3) The technical parameters of the device, including waveform, output modes, maximum output voltage and current (with 500, 2,000, and 10,000 ohm loads), pulse duration, frequency, net charge (µC) per pulse, maximum phase charge at 500 ohms, maximum current density (mA/cm 2 , r.m.s.), maximum average current (mA), maximum average power density (W/cm2 ), and the type of impedance monitoring system must be fully characterized.(4) Electrical performance, adhesive integrity, shelf life, reusability, and current distribution testing of the electrodes must be conducted. (5) Appropriate software verification, validation, and hazard analysis must be performed. (6) Clinical performance data must demonstrate that the device is safe and effective as a treatment for headache in the indicated patient population. (7) Labeling must include the following: (i) Appropriate contraindications such as not for use in subjects with an implanted metallic or electronic device in the head, a cardiac pacemaker, or an implanted or wearable defibrillator. (ii) Appropriate warnings such as not to apply the device on the neck or chest, not to use the device in the presence of electronic monitoring equipment, not to use in the bath or shower, not to use while sleeping, not to use while driving, not to use while operating machinery. (iii) Appropriate precautions such as the long-term effects of chronic use of the device are unknown. (iv) A summary of the expected risks and benefits of using the device. (v) A summary of the clinical performance data, including information on the patient population for which the device has and has not been demonstrated to be effective, and any adverse events and complications. (vi) Information on how the device operates and the typical sensations experienced during treatment. (vii) A detailed summary of the device technical parameters. (viii) An expiration date/shelf life for the electrodes and the number of times they can be reused. (ix) Disposal instructions.
In combination with the general controls of the Food Drug & Cosmetic Act, the Transcutaneous Electrical Nerve Stimulator to Treat Headache is subject to the following special controls:
Predicate Devices
- CEFALY Connected – OTC (K234029)
Submission Summary (Full Text)
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FDA U.S. FOOD & DRUG ADMINISTRATION
April 16, 2026
Hinge Health, Inc.
Roop Pandher
Staff Engineer, Regulatory and Quality
455 Market St., Suite 700
San Francisco, California 94105
Re: K254216
Trade/Device Name: Enso for Migraine
Regulation Number: 21 CFR 882.5891
Regulation Name: Transcutaneous Electrical Nerve Stimulator To Treat Headache
Regulatory Class: Class II
Product Code: PCC
Dated: December 24, 2025
Received: December 29, 2025
Dear Roop Pandher:
We have reviewed your section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (the Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database available at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
Additional information about changes that may require a new premarket notification are provided in the FDA guidance documents entitled "Deciding When to Submit a 510(k) for a Change to an Existing Device"
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(https://www.fda.gov/media/99812/download) and "Deciding When to Submit a 510(k) for a Software Change to an Existing Device" (https://www.fda.gov/media/99785/download).
Your device is also subject to, among other requirements, the Quality Management System Regulation (QMSR) (21 CFR Part 820), which includes, but is not limited to, ISO 13485 clause 7.3 (Design controls), ISO 13484 clause 8.3 (Nonconforming product), and ISO 13485 clause 8.5 (Corrective and preventative action). Please note that regardless of whether a change requires premarket review, the QMSR requires device manufacturers to review and approve changes to device design and production (ISO 13485 clause 7.3 and 21 CFR 820.70) and document changes and approvals in the device master record (21 CFR 820.181).
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); medical device reporting (reporting of medical device-related adverse events) (21 CFR Part 803) for devices or postmarketing safety reporting (21 CFR Part 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reporting-combination-products); good manufacturing practice requirements as set forth in the Quality Management System Regulation (QMSR) (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR Part 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR Parts 1000-1050.
All medical devices, including Class I and unclassified devices and combination product device constituent parts are required to be in compliance with the final Unique Device Identification System rule ("UDI Rule"). The UDI Rule requires, among other things, that a device bear a unique device identifier (UDI) on its label and package (21 CFR 801.20(a)) unless an exception or alternative applies (21 CFR 801.20(b)) and that the dates on the device label be formatted in accordance with 21 CFR 801.18. The UDI Rule (21 CFR 830.300(a) and 830.320(b)) also requires that certain information be submitted to the Global Unique Device Identification Database (GUDID) (21 CFR Part 830 Subpart E). For additional information on these requirements, please see the UDI System webpage at https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance/unique-device-identification-system-udi-system.
Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-devices/medical-device-safety/medical-device-reporting-mdr-how-report-medical-device-problems.
For comprehensive regulatory information about medical devices and radiation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).
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Sincerely,
JITENDRA V. VIRANI -S
CDR Jitendra Virani, MS, MBA
Assistant Director
DHT5B: Division of Neuromodulation and
Physical Medicine Devices
OHT5: Office of Neurological and
Physical Medicine Devices
Office of Product Evaluation and Quality
Center for Devices and Radiological Health
Enclosure
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FORM FDA 3881 (8/23)
Page 1 of 1
PSC Publishing Services (301) 443-6740
EF
| DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration Indications for Use | Form Approved: OMB No. 0910-0120 Expiration Date: 07/31/2026 See PRA Statement below. |
| --- | --- |
| 510(k) Number (if known) K254216 | |
| Device Name | |
| Enso for Migraine | |
| Indications for Use (Describe) | |
| Enso for Migraine is indicated for patients 18 years of age or older for acute treatment of migraine with or without aura and preventative treatment of migraine. Enso for Migraine is for patients diagnosed with migraine by a physician. | |
| Type of Use (Select one or both, as applicable) ☐ Prescription Use (Part 21 CFR 801 Subpart D) ☑ Over-The-Counter Use (21 CFR 801 Subpart C) | |
| CONTINUE ON A SEPARATE PAGE IF NEEDED. | |
| This section applies only to requirements of the Paperwork Reduction Act of 1995. *DO NOT SEND YOUR COMPLETED FORM TO THE PRA STAFF EMAIL ADDRESS BELOW.* | |
| The burden time for this collection of information is estimated to average 79 hours per response, including the time to review instructions, search existing data sources, gather and maintain the data needed and complete and review the collection of information. Send comments regarding this burden estimate or any other aspect of this information collection, including suggestions for reducing this burden, to: Department of Health and Human Services Food and Drug Administration Office of Chief Information Officer Paperwork Reduction Act (PRA) Staff PRAStaff@fda.hhs.gov | |
| "An agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a currently valid OMB number." | |
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Hinge Health
# 510(k) Summary
The following information is provided in accordance with 21 CFR 807.92.
| 510(k) Submitter | Hinge Health Inc.
455 Market Street
Suite 700
San Francisco, CA 94105 |
| --- | --- |
| Contact Person | Roopkamal Pandher
Staff Engineer Regulatory & Quality
Hinge Health
Email: roopkamal.pandher@hingehealth.com
Tel: +1 (855) 902-2777 |
| Date Prepared | April 16, 2026 |
| Common Name | Transcutaneous electrical nerve stimulator to treat headache |
| Device Trade Name | Enso for Migraine |
| Classification | Class II |
| Regulation | 21 CFR 882.5891
Transcutaneous electrical nerve stimulator to treat headache |
| Product Code | PCC |
| Panel | Neurology |
| Proposed Predicate Device | K234029
CEFALY Connected – OTC
21 CFR 882.5891, PCC, Class II |
# Device Description:
The Enso for Migraine is an over-the-counter medical device that is intended to be used by patients 18 years of age or older for the acute treatment of migraine with or without aura and the preventative treatment of migraine. The Enso for Migraine is a wearable, app-controlled system that can be used to excite nerves in the head via transcutaneous electrical nerve stimulation ("TENS") to create a neuromodulation effect that reduces the severity and frequency of migraines.
The Enso for Migraine system includes the following physical components: the Enso Device (the TENS unit), reusable and disposable self-adhesive hydrogel pads ("gel pads"), a charging dock, cable, and AC adapter for recharging, disposable skin wipes, a paper copy of the user manual and quick start guide, and a bag for storage between sessions. The Enso Device attaches by magnets to a
510(k) Summary
Traditional 510(k) - Enso for Migraine
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Hinge Health
cradle on the gel pad, which is adhered to the skin for a treatment session. The Enso Device delivers transcutaneous electrical stimulation via electrodes integrated into the gel pad.
The Enso Device is controlled wirelessly using the Hinge Health mobile application ("App"), which has been downloaded by the user to a compatible mobile device. The App allows the user to administer the TENS treatment session and control treatment settings.
## Intended Use:
The predicate and subject devices share an intended use, namely the application of an electrical current through electrodes placed on the skin to treat headache in adults.
Table 1. Indications for Use comparison
| | Predicate Device
K234029 Cefaly Connected - OTC | Subject Device
Enso for Migraine |
| --- | --- | --- |
| Indications for Use | Cefaly Connected - OTC is indicated for:
1. Acute treatment of migraine with or without aura in patients 18 years of age or older
2. Preventative treatment of migraine in patients 18 years of age or older | Enso for Migraine is indicated in patients 18 years of age or older for the acute treatment of migraine with or without aura and the preventative treatment of migraine.
Enso for Migraine is for patients diagnosed with migraine by a physician. |
Although the formatting differs slightly, the language and meaning are the same and the subject statement conveys the same intended use as the predicate.
## Technological Characteristics:
The table below provides a comparison of the technological characteristics of the predicate and subject devices. Where there are differences, a discussion of why they do not raise issues of safety and effectiveness is included below the table under the referenced header.
Table 2. Comparison of technological characteristics
| | Predicate Device
K234029 Cefaly Connected - OTC | Subject Device
Enso for Migraine | Comparison | Impact |
| --- | --- | --- | --- | --- |
| Indications for Use | Acute and preventative treatment of migraine, ≥18 yrs | Acute and preventative treatment of migraine, ≥18 yrs | Same | Equivalent Indications |
510(k) Summary
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| | Predicate Device K234029 Cefaly Connected - OTC | Subject Device Enso for Migraine | Comparison | Impact |
| --- | --- | --- | --- | --- |
| Operating Principle | TENS via hydrogel pad/electrode to forehead | TENS via hydrogel pad/electrode to forehead | Same | Not Applicable |
| Placement | Center of forehead | Center of forehead | Same | Not Applicable |
| TENS System Components | Neurostimulator, gel pad, charging dock/cable, mobile app | Neurostimulator, gel pad, charging dock/cable, mobile app, skin wipes | Different | Subject device includes cosmetic skin wipes for convenience (no impact on safety/effectiveness) |
| Neurostimulator Dimensions/ Weight | 66×47×17 mm / 25g | 42×42×11 mm / 13.5g | Different | Smaller form factor increases portability, no functional impact |
| Battery | 3.7V rechargeable LiPo | 3.85V rechargeable LiPo | Different | No functional impact; compatible with circuitry; similar battery life |
| Controls/ User Interface | On-device multi-function button and app | Functions via mobile app, single on-device button | Different | Predicate: Treatment selection via device/app; Subject: All selection via app. Both allow safe treatment stop. No safety/effectiveness impact. |
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| | Predicate Device K234029 Cefaly Connected - OTC | Subject Device Enso for Migraine | Comparison | Impact |
| --- | --- | --- | --- | --- |
| Visual/Audio Indicators | Visual indicators plus audio signals | Visual indicators only (via device + app) | Different | Audio indicator absent in subject; not necessary due to app-based controls. No impact. |
| Electrode (Gel Pad) Size/Shape | 94×20 mm | 86×49 mm | Different | Subject is larger; ensures similar current delivery, lowers current density. Safe and effective. |
| Electrode Material | Acrylic hydrogel | Acrylic hydrogel | Same | Not Applicable |
| Bluetooth Connectivity | Yes | Yes | Same | Not Applicable |
| Channels | 1 | 1 | Same | Not Applicable |
| Output modes | • Preventative
• Acute | • Preventative
• Acute (called 'Calm') | Same | Not Applicable |
| Max Output Current (mA) | 16 (at 500/2000 Ω), 6 (10,000 Ω) | 15 (at 500/2000 Ω), 7 (10,000 Ω) | Slightly Different | 1 mA difference, not clinically significant. Variability in patient use outweighs difference. |
| Max Output Voltage (V) | 8 (500 Ω), 32 (2000 Ω), 60 (10,000 Ω) | 8 (500Ω), 30 (2000Ω), 73 (10,000Ω) | Slightly Different | Reflects output specs and pad design. No safety concern. |
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| | Predicate Device K234029 Cefaly Connected - OTC | Subject Device Enso for Migraine | Comparison | Impact |
| --- | --- | --- | --- | --- |
| Waveform | Biphasic, symmetric, rectangular, fully compensated | Biphasic, asymmetric, rectangular, fully compensated | Different (Recovery phase) | Both achieve zero net charge/pulse. No impact; both used in TENS. |
| Maximum current density (mA/cm2, r.m.s.) at 500 ohms | 2.37 | 1.09 | Different (Lower in subject) | Lower density due to larger pad; reduces risk of hotspots. |
| App Features | Treatment session control, intensity adjustment, logs | Treatment session control, intensity adjustment, logs | Same | Not Applicable |
| Biocompatibility /Electrical Safety | Compliant (per predicate K234029) | Compliant (IEC 60601, ISO 10993) | Same | Both meet applicable standards (per performance data) |
| Net charge (μC) per pulse | 0 | 0 | Same | Not Applicable |
| Maximum Phase Charge (μC) at 500 ohms | 4 | 4 | Same | Not Applicable |
| Type of impedance monitoring system | Electrical | Electrical | Same | Not Applicable |
| PREVENTATIVE Amplitude (mA) | 0 - 16 | 0 - 15 | Different | 1 mA difference, not clinically significant. |
| PREVENTATIVE Pulse active phase width (μs) | 250 | 249 | Different | Minor differences (1 μs) not clinically relevant. |
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| | Predicate Device K234029 Cefaly Connected - OTC | Subject Device Enso for Migraine | Comparison | Impact |
| --- | --- | --- | --- | --- |
| PREVENTATIVE Pulse frequency (Hz) | 60 | 60 | Same | Not Applicable |
| PREVENTATIVE Pulse duration (μs) | 505 | 516 | Different | Minor difference in recovery phase duration not clinically significant. |
| PREVENTATIVE Session duration (min) | 20 | 20 | Same | Not Applicable |
| PREVENTATIVE Maximum average current (average absolute value, mA) at 500 ohms | 0.48 | 0.31 | Different | Difference arises from the subject device using passive rather than active recovery - no clinical impact, given that primary active phases are comparable. |
| PREVENTATIVE Maximum average power density (W/cm2) at 500 ohms | 0.000017 | 0.00020 (*0.000011) | Different | Difference arises from the subject device using passive rather than active recovery - no clinical impact, given that primary active phases are comparable. |
| ACUTE Amplitude (mA) | 0 - 16 | 0 - 15 | Different | 1 mA difference, not clinically significant. |
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| | Predicate Device K234029 Cefaly Connected - OTC | Subject Device Enso for Migraine | Comparison | Impact |
| --- | --- | --- | --- | --- |
| ACUTE Pulse active phase width (μs) | 250 | 249 | Different | Minor differences (1 μs) not clinically relevant. |
| ACUTE Pulse frequency (Hz) | 100 | 101 | Different | Minor differences (1 Hz) not clinically relevant. |
| ACUTE Pulse duration (μs) | 505 | 510 | Different | Minor difference in recovery phase duration not clinically significant. |
| ACUTE Session duration (min) | 60 | 60 | Same | Not Applicable |
| ACUTE Maximum average current (average absolute value, mA) at 500 ohms | 0.8 | 0.51 | Different | Difference arises from the subject device using passive rather than active recovery - no clinical impact, given that primary active phases are comparable. |
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| | Predicate Device K234029 Cefaly Connected - OTC | Subject Device Enso for Migraine | Comparison | Impact |
| --- | --- | --- | --- | --- |
| ACUTE Maximum average power density (W/cm2) at 500 ohms | 0.000047 | 0.00033 (*0.000029) | Different | Difference arises from the subject device using passive rather than active recovery - no clinical impact, given that primary active phases are comparable. |
# Summary of Differences
The subject Enso for Migraine and the predicate Cefaly Connected – OTC share the same intended use and fundamental TENS mechanism. There are several minor technological differences between the two devices. The Enso for Migraine features a smaller, lighter neurostimulator; a slightly higher voltage battery; and relies primarily on a mobile app for treatment control, whereas the predicate uses both an on-device button and app. The subject device's gel pad is larger and differently shaped, resulting in a lower maximum current density, and it employs an asymmetrical biphasic waveform for charge recovery instead of the predicate's symmetrical approach. The larger gel pad area contributes to lower maximum current density while maintaining comparable current amplitude, which does not reduce treatment effectiveness as current is not required to be tightly distributed in one spot for stimulation of superficial trigeminal nerve branches. Finite element modeling studies comparing the predicate's gel pad geometry with larger and more extended geometries found that the larger pad produced "negligible impact on the induced current flow pattern" in target nerves, spreading the same magnitude of induced field into the same nerve branches while providing safety benefits through reduced current density (Thomas et al., "Determination of Current Flow Induced by Transcutaneous Electrical Nerve Stimulation for the Treatment of Migraine: Potential for Optimization." Front. Pain Res. Lausanne Switz. 2021). Output parameters such as current, voltage, and frequency are similar, with only small differences that are not clinically significant. The Enso for Migraine app omits some optional tracking and reminder features found in the predicate's app, and its packaging includes additional items such as cosmetic skin wipes and a quick start guide. None of these differences raise new questions of safety or effectiveness, and bench testing confirms that the Enso for Migraine performs equivalently to the predicate device.
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# Performance Testing - Bench
Performance testing was completed to confirm that the device meets established specifications and requirements.
Non-clinical testing was performed to evaluate key aspects of device performance:
- Therapeutic Performance
- including waveform characteristics, current density, and distribution
- Gel Pad and Skin Interface Performance
- including adhesion, impedance, and reuse characteristics
Results of non-clinical bench testing are sufficient to demonstrate safety and effectiveness of the subject device and support a determination of substantial equivalence to the predicate, so animal and clinical performance testing were not necessary.
A human factors study was also completed to support a determination of substantial equivalence to the predicate and to establish safety and effectiveness of the subject device for an over-the-counter indication.
Results of performance testing (bench and human factors) demonstrated that the subject device is as safe and effective as the predicate with respect to the intended use.
# Performance Testing - Clinical
Clinical performance testing was not conducted for the subject device. Instead, clinical effectiveness and safety were established via analysis of published clinical literature for the legally marketed predicate device.
# Conclusion
The subject and predicate devices share a common intended use, and the differences in technological characteristics do not raise issues of safety and effectiveness. Results of performance testing demonstrate that the subject device is as safe and effective as the predicate with respect to the intended use. Therefore, the subject device can be concluded to be substantially equivalent to the predicate.
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