There are a lot of devices on the market advertised as being effective against pain. Often the advertising may seem quite persuasive and make many claims:
- Approved by the FDA for pain relief!
- Prescribed by hundreds of doctors!
- Shown to be effective by dozens of scientific studies!
But do any of these devices actually work?
Testing Pain and the Placebo Effect
In many cases, the question is not easy to answer, because of two factors:
- The device in question usually has not been tested very carefully using reliable methods, and
- Pain is subject to a very strong placebo effect – in other words, if people can be made to believe that a device is effective, they are very likely to perceive it as effective.
Furthermore, some of the most common types of pain, such as arthritis or muscle pain, can easily be reduced by warmth or exercise. This means it is possible for devices to be effective in ways that have nothing to do with the claims made about them by marketers – and in many cases, much cheaper solutions are available.
FDA Approval Is a Low Bar
One big claim about many pain gadgets is that they have somehow been stamped by a federal agency. Many pain relief devices on the market are advertised as “FDA approved” or “FDA cleared” or some similar wording. When you see a claim like that, you might be tempted to think that the FDA has carefully evaluated the device and found that it is effective against pain.
But that isn’t generally true. In reality all it usually means is that the FDA has no compelling reason to think the device is dangerous. Sometimes it doesn’t even mean that, but only that similar devices have been allowed to be sold in the past.
There are, indeed, situations where the FDA goes through a careful and thorough evaluation of the effectiveness of a device – but the only way to tell is to examine the specific statement released by the FDA. As the marketers behind these gadgets know, however, very few people actually take the time to look up what the FDA actually said.
Most of the pain relief gadgets discussed below have been FDA-cleared under a process known as 501(k), where the main criterion is that the device does not differ substantially from devices that have been approved in the past. A 501(k) clearance carries no information about effectiveness. At best it means that the FDA didn’t find anything extremely harmful – though, future reports of injuries could change that designation.
Specific Pain Devices
Below, we’ve put together a list of some of the most popular types of pain relief gadgets currently on the market with some notes about their effectiveness. Each product has its own idiosyncrasies, but the bottom line is that most of these devices are probably safe when used as directed – although there is no high-quality evidence that they are more effective than placebo.
With that in mind, let’s look in more detail at a few specific categories of devices.
TENS: Transcutaneous Electrical Nerve Stimulation
The concept of TENS is to attach conductive pads to the skin near the pain site, and use them to stimulate the tissue with a moderately intense low-frequency electric current.
TENS devices have been marketed since 1974, and similar devices go back as far as the 19th century. They have been tested in many experimental studies, but academic authors who have reviewed the entire range of studies have found very weak evidence for their overall effectiveness.
There are, however, exceptions. This is a complex topic, and it is easy to find studies supporting any given opinion. In any case, if TENS devices are used at recommended current levels they are probably pretty safe. It is generally recommended to keep the conductor pads away from the head and heart, and people with pacemakers or other implanted devices definitely should not use these machines. Otherwise, the voltages involved probably not high enough to be dangerous for most healthy people.
PEMF: Pulsed Electromagnetic Fields
Like TENS these devices rely on electricity, but instead of passing current through the tissue using attached electrodes, they use magnetic coils to create electromagnetic fields that permeate the environment. PEMF devices are more complex than TENS devices, and quite a bit more expensive.
There is reasonably strong evidence that PEMF can promote healing of broken bones, but there have been very few reliable scientific studies on its effects on pain. Systematic reviews have generally little evidence that PEMF devices are effective.
That said, there is some reason to think PEMF may be moderately effective for arthritis in the knees. In any case, for those who want to try it, the device itself is probably safe, as the fields it generates are not strong enough to be dangerous.
LLLT: Low-Level Laser Therapy
LLLT refers to a large group of devices that purport to treat pain by shining a red or near-infrared laser light at a weak intensity on the skin. Many such devices have received 501(k) clearances, and some have been very aggressively marketed.
The most notorious example is the Anodyne Therapy System, which has been marketed for over 20 years and has been the subject of FDA “cease and desist” actions because of unjustified claims in its marketing literature. LLLT devices are probably safe unless misused, and probably have some effect on some types of pain; but the question is, do they have any effect beyond that which results from the warmth that they produce?
There does not seem to be any solid evidence that they do. The most careful reviews have not found good evidence that they reduce pain any more effectively than other warming agents such as a heating pad.
Ultrasound devices make use of high-frequency sound waves. Ultrasound is used in many ways in medicine, and there is no question that it is effective for many purposes, including imaging the interior of the body and cutting tissue for surgery. The ultrasound devices available for home use, however, generate energies that are too low to be harmful, and as a consequence, perhaps too low to be very helpful.
Ultrasound has been tried on many types of pain. For most of them the evidence is too limited to make any strong statement; however a recent review from the Cochrane Collaboration suggests that it might be moderately helpful for osteoarthritis of the knee. As for laser light, however, there is a question whether the effects go beyond those of the tissue warming that ultrasound produces.
In Pain? See Your Doctor!
The bottom line, applicable to pretty much any pain relief device available to the public, is that if it is advertised as “FDA approved” then it is probably safe when used as directed (but to be sure you can always check the FDA web site yourself). Prudence dictates, however, a healthy level of skepticism regarding whether the device is actually as effective as it claims to be.
If you are experiencing chronic pain, you should talk to your doctor. Pain can often be a sign of underlying problems that may be treatable or even curable. Even when it isn’t, you can at least avoid paying for expensive equipment that make unproven claims at best.
Have You Used a Pain Relief Gadget Before?
If you’ve used a device for relieving pain, and either loved it, or felt it did nothing for you, let us know in the comments below!