Although both of these conditions contain the word "arthritis", if you suffer from either one you know that they are very different. We have found, for example, that contrary to what we expected—rheumatoid arthritis seems to respond much more quickly to use of the MicroStimula MK II than Osteoarthritis. Both require regular use, preferably daily but the feedback that we get indicates that it can take up to six months to notice changes in Osteoarthritis. While Rheumatoid Arthritis patients find that the pain may be relieved earlier than that. Joint swelling and mobility changes in osteoarthritis occur slowly over time. Rheumatoid Arthritis users seem to respond much more quickly which makes sense when you think about it. It can take a long time for osteoarthritis to do significant damage to the joints while Rheumatoid Arthritis can cause pain and inflammation very quickly and it can move from joint to joint in the body. Normalizing the cells right away possibly provides more immediate relief as well as preventing the lasting damage or RA. The jury is out on this one but we do have a number of users who tell us that they are much more comfortable and mobile that they were prior to use of the device. We would appreciate your feedback.