While a majority of reviews of the TENS medical device on Amazon.com are positive, some reviews are negative. Many reviewers rate the device as highly effective for pain relief, while others state that, while it helps their pain, the TENS belt and snaps lack durability.
Inconclusive results of four scientific studies comparing the effectiveness of the TENS device to a placebo fail to prove its effectiveness in relieving pain, according to WebMD. Many reviewers on Amazon.com report that the device is easy to use, and that it works as well as the professional devices used by their medical providers. Others report issues in which the device either stopped working or the snaps that attach the electrodes came off the belt.