Can you trick your brain into not feeling pain — without medication? We’ve used electricity to do that for centuries, but this method is newly popular again. Transcutaneous electrical nerve stimulation, or TENS, has become far more accessible since it was approved as an over-the-counter treatment by the US Food and Drug Administration about two years ago. Now, with the country in the midst of an opioid epidemic, doctors and patients and medical-device manufacturers are paying more attention to this form of natural pain management.
Think of the machines as “using electricity to rub away pain,” says Mark Johnson, a professor of analgesia at Leeds Beckett University in the United Kingdom. TENS devices are portable machines with electrodes. You put the electrodes wherever you have muscle pain, turn on the device, and feel a tingling sensation. The machine sends electrical pulses through your skin and nerves. The electrical pulses do two things: first, it distracts the brain to prevent the pain signals from reaching the brain. Second, it encourages your body to produce more of its own natural painkillers.
The Verge’s Natt Garun tried several TENS devices made by AccuRelief at this year’s Consumer Electronics Show, as did I, separately. I used mine on my forearm and found the tingling feeling rather uncomfortable. Natt’s device, placed on her shoulders, went to 60; at the 35 setting, she was bouncing around and finding it difficult to type properly. That said, neither of us have severe muscle pain, so it’s difficult for us to evaluate the effectiveness. (Also, the highest setting is usually reserved for people with serious chronic pain. Higher settings are also important because tolerance for the electrical signals does build.)
Using electricity to manage pain has a long history, says Kathleen Sluka, a professor of physical therapy at the University of Iowa. Ancient Egyptians used electric eels for this very purpose and, in the 1800s, doctors helped their patients by using a device with a crank that created electrical output. Physical therapist have used TENS devices for years in clinical settings for both chronic pain and acute pain, and they can also be helpful for routine soreness from exercise. “TENS is easy and safe and it’s been around for a long time,” says Sluka. “Most of what you’re seeing now is people finally bringing it to the community.”
Despite the long history, the basic technology hasn’t changed much in the past few decades, says Johnson. Researchers have long tried to find the “magic bullet” — a particular pulse or pattern of electricity that will make it suddenly much more effective — but there haven’t been many breakthroughs.
But, since FDA approval, there are plenty of inexpensive TENS devices available at drugstores like Walgreens and Rite Aid. These new devices come in a lot of different shapes and sizes and many are wireless, which is convenient for patients who wear them anywhere from 30 minutes a day to all day. AccuRelief, for example, recently debuted a few new TENS models that can be controlled using an app instead of with a traditional remote. One of these, called TheraMed, is a device for athletes that will launch later this year.
The market for TENS is small, but growing very quickly, says Jeff Swains, vice president of marketing for AccuRelief parent company Compass Health Brands. “Doctors and pharmacists are starting to get pressure from government bodies around cutting back opioid prescriptions,” he says. “We have customers that are healthcare organizations and they recognize the cost associated with opioids, so they’re invested in actually trying to give away devices to the people on their plans because it’s less expensive than opioids and there’s no chance of being addicted.”
It’s unlikely that a device from the drugstore is just as effective as a powerful opioid, and there has been some debate on the effectiveness of the devices. One Cochrane review concludes that the effectiveness is mixed, but because the device is so cheap and safe, there’s no real harm in trying. Johnson, from Leeds Beckett University, disagrees with reviews that say TENS is not effective because there isn’t enough good-quality evidence. A lot of the current studies are done on small sample sizes, he says. Plus, the studies cite the average result, even when the feedback skew on extreme ends of the spectrum. (Dana Dailey, a professor of physical therapy at the University of Iowa, is currently running a study looking at both the long-term use of TENS, since previous studies look at it for only a few days.)
Sluka agrees that TENS isn’t for everyone. “Some people absolutely love them and some people can’t stay in the study because they can’t handle it,” says Sluka. Is it as effective as opioids? Maybe not, she says. But it’s usually at least as effective as ibuprofen, if not more. The devices can be useful when part of a broader treatment program, are alternative to ingesting drugs, and don’t have dangerous side effects. (More recently, some similar devices are using electrical signals to try to fix mental stress, too.)
Right now, we don’t know a lot about who will benefit most from the devices. We know more about who shouldn’t use it, notably people with implanted pacemakers. Other research has suggested that people who have more anxiety and depression tend to not do as well, according to Dailey. “It tends to be more physically uncomfortable to them, and they’re more likely to find it painful,” she says. In terms of effectiveness, people who sweat a lot or have a lot of oil in their skin might have more trouble getting the electrodes to stick.
If you’re interested in testing TENS, there are a few things to keep in mind. You need to turn up the intensity as high as you can take it, according to Sluka. It’s not enough to just get a little tingling sensation (like I did). That’s not very effective. And though tolerance build-up is a risk, having the device on too low a setting defeats the purpose to begin with.
When choosing a device, take a close look at the size and length of the electrodes. The biggest expense for this unit will be replacing those electrodes, which could happen as often as every few weeks. Make sure the electrodes aren’t too expensive to replace, and also that they will fit on whatever part of your body you will be using the device on. The neck, for instance, is probably one of the hardest places to put a TENS unit on since there’s less surface area and people do use their necks a lot.
For those itching to try this for themselves, they’re easily available and usually range from about $30 to $100. Unless you’re very sensitive to sensation, it basically can’t hurt to try.