Most published CES research studies were conducted at either 100 uAmp or 200 uAmp. The reason for this is that such a level is so low that the human skin cannot feel it. In other words, some study participants can be actively treated and others can be given sham ‘fake treatment – neither study participant would know which was which. This is done to eliminate the possibility of “positive thinking” influencing the research results. To get to the point: 200 uAmp for CES is quite enough to get effects. However, if you prefer to feel some tingling sensation at the contact points, you can increase the level beyond 200 uAmp. For MET, the optimal intensity is determined by increasing the intensity until you just-just can feel a tingling sensation. You can stop at this level.