I've used it for a couple of months. It is a very powerful unit and one can burn themselves if not careful. If you purchase one, read the instructions and be careful. If set too high, the unit will burn you rather severely. I'm speaking from experience since I used it on high for less than a minute. I noticed a difference almost immediately with pain. Other positive effects took a couple of weeks on the lowest setting 2 times daily for about 3 minutes each time. I can't say that this is reversing my PN but the pain levels are down and my swelling is down.