The Science behind Quell Electrodes

08/09/2017 • Quell Team

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Katecho Electrode

Quell electrodes may look unassuming, but they are key to enabling a pocket-sized device to deliver clinical strength therapy for drug-free pain relief. Quell electrodes are proprietary, which means that they were designed and manufactured specifically for our Quell Wearable Pain Relief Technology. Our Boston-based engineering team has spent over 20 years developing nerve stimulation technologies for use in NeuroMetrix’s clinical diagnostic products and they leveraged this expertise to design the Quell electrodes. Our electrodes are made in the USA by our partner that specializes in medical manufacturing. Quell electrodes look and perform in a very distinctive way and we’d like to answer some of the questions people have about what makes them different.

Why are the electrodes so big?

Quell is designed to stimulate a large area of nerves in a precise way. Quell electrodes incorporate 4 strategically spaced pads into one long, flexible strip that snaps onto the back of the device. Quell provides pain relief by comfortably stimulating the nerves that carry normal, non-painful sensations, which decrease the perception of pain. No training or expertise is required for correct placement. As long as you place your Quell 1-2” below the knee, the device will be positioned correctly.

What’s special about the gel?

The hydrogel pads that come on the Quell electrodes are optimized to deliver high-powered neurostimulation in a controlled fashion. The hydrogel is tested for biocompatibility and designed for long-term wear.  For a typical user and with proper care (see our Electrode Care Tips) a single electrode will last approximately two weeks. Because the gel on Quell electrodes is primarily water, the gel pads may show signs of wear during the course of normal use, which can include irregular edges on the gel pads, gel spreading, color fading, or some of the underlying silver traces becoming exposed. Although the electrode gel won’t look as nice as it did when it first came out of the package, rest assured that it is safe to use as long as therapy feels comfortable and you aren’t seeing an orange light on your device.

Why are there snaps on the electrodes?

The Quell device connects to the electrodes via snaps, so there are no lead wires to worry about and the user can go about their daily activities or sleep while wearing the device. The snaps conduct the energy from the device to the silver array that you see under the gel pads. A conventional TENS device typically includes a control unit and individual electrode pads, which are connected to the control unit by wires. These wires and individual electrodes inhibit the user’s movement and may require you to remain stationary throughout the entire therapy session.

What about safety?

Quell is designed to automatically shut off if the electrode isn’t making adequate contact with the skin, which is why it is the only device of its kind available without a doctor’s prescription that is cleared by the FDA for use during sleep.*

Is it safe to use other electrodes with Quell?

Quell is a Class II medical device and the FDA has not cleared any third-party electrodes for use with Quell. All safety and clinical validations were completed using Quell electrodes. Quell is a high powered neurostimulator and the safety and efficacy of using alternative electrodes has not been proven.

Product innovation

We want to make sure you have the best experience possible with Quell and continually strive to improve the product based on user feedback. For example, we introduced a Sport version of the electrode last year that absorbs less moisture to address the needs of Quell users who live in humid climates or have higher amounts of perspiration. Quell will continue to evolve and improve as we incorporate your feedback into future design improvements.


*FDA 510(K) clearance means that the FDA has deemed the device to be as safe and effective as a medical device previously cleared by the FDA; this is called “substantially equivalent.” This process is different from FDA approval of drugs and typically does not involve a review and analysis of clinical data. All transcutaneous electrical nerve stimulators (TENS) must be FDA cleared before they are marketed. The FDA 510(k) clearance for Quell specifically states that it may be used during sleep.

About The Author
Quell Team

The Quell Team is comprised of members of the Marketing, Engineering and Customer Care teams at NeuroMetrix. We are committed to empowering people living with chronic pain to regain a high quality of life. We believe that life shouldn’t be defined by a condition. We believe that no one should have to settle for crippling side effects and we imagine a future where therapies are accessible, available and usable for anyone who needs it.

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