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What Does “Prescription Strength” TENS Mean?

09/08/2020 • Shai Gozani M.D., Ph.D.


Many over-the-counter (OTC) TENS devices claim to be “prescription strength.”  What does that actually mean and is it an important distinction?  In this post we will define prescription strength TENS and examine its use in TENS marketing.

Prescription Strength TENS

An OTC treatment that is prescription strength is one that is as strong as a prescription version of the same treatment.  Applied to TENS, this means that the device can generate as much electrical power as a typical prescription TENS device.  Electrical power is determined by multiplying the voltage by the current, two of the most important TENS technical specifications.  We have discussed both in previous posts, so please go to “Under the Hood – Maximum Voltage” and “Under the Hood – Stimulation Pulse” to learn more.  So how much electrical power is needed to be called prescription strength? A reasonable definition is the specifications of the leading prescription TENS device, which are 100 volts and 100 milliamps.

Advantages of Prescription Strength TENS

To produce pain relief, a TENS device must stimulate a sufficient number of nerves.  Moreover, activation of deep nerves, which requires higher power, may provide more pain relief than superficial nerves. In general, younger, thinner and healthier people require less power than those who are older, overweight and have multiple medical conditions.  Because physicians often prescribe TENS for patients that are older and who have medical conditions, they prefer high power devices.

Comparison of Electrical Power

Most OTC TENS devices use basic electronic circuits that produce limited electrical power. Prescription TENS devices are usually more sophisticated and capable of generating up to three times more power than typical OTC devices.  Quell® is unique among OTC TENS devices.  It has advanced stimulation electronics that produce the highest stimulation power among all widely available TENS devices.  See the chart below for a comparison of electrical power among TENS devices.

  Maximum Instantaneous Power (Watts) Source

Quell 2.0



Leading prescription TENS



Typical “Prescription Strength” OTC TENS



Power calculated from maximum output voltage over 2000-ohm resistive load (P = V2/2000). Data taken from 510(k) (listed reference) and user manual.


As the chart shows, although OTC TENS devices may be described as prescription strength, they generally do not meet the technical specifications of a prescription TENS device.

About The Author
Shai Gozani M.D., Ph.D.

Dr. Gozani is an expert in non-invasive neurostimulation. He received his M.D. degree from Harvard Medical School and the Harvard-MIT Division of Health Science and Technology. Dr. Gozani earned his Ph.D. in Neurobiology, M.S. in Electrical Engineering & Computer Science and B.A. in Computer Science from the University of California at Berkeley. Following his studies, Dr. Gozani conducted post-doctoral research at Harvard Medical School and MIT. He holds 36 U.S. patents and has authored over 30 articles in scientific and clinical peer-reviewed journals. Dr. Gozani is founder, president and CEO of NeuroMetrix, Inc.; which designs and manufactures Quell.

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