I've been using a zapper - a design quite similar to but yet different from the Clark Zapper, for about 15 months now. From what I have observed in my own use as well as what I've gathered from reading numerous related forums, there is no one-size-fits-all to the various experiences and questions that may arise regarding the zapper. We are all a bit different despite the many things we all have in common, so keep this in mind that your experience may vary.
I began zapping having done nothing / zero prior to specifically address related parasite
concerns, such as liver flushing, bowell cleansing, adjustments to diet, etc. I will add that in an unrelated effort, for close to 6 months prior to first zapping, I started using Dr. Schulze
's #2 formuala (clay and flax formula) mixed in with my daily morning mega dose of vitamin C, just as a general effort to do some bowel cleansing, so this may have unknowingly provided me some head start or benefit when I eventually discovered the parasite
issue and began zapping.
I have not expereinced any obvious negative effects from zapping. I'm only saying it this way because I want to acknowledge that there may be (or have been) negative effects beyond my knowledge or awareness, but as far as I can tell - feel / see, sense, there have been none. Conservatively speaking, my health is at least as good and probably a bit better since I began zapping, but Zapping is not the only change I've added to my health regimen in the last 12 months. Keep in mind that I'm not one of "those" to make a big deal or lawsuit out of a tiny red spot or skin irritation that may have resulted from leaving the zapper on one sensitive spot of skin for too long. If something as mild as this concerns you, then yes, be aware, you may develop some small welts from leaving the zapper on a sensitive area too long. Generally, the tougher the area of skin that the zapper is placed on, like on the heals or palms, the less the chances that such minor irritations will happen. Also, the moister the skin (especially during hot/muggy weather), the better the conductivity and the better the chances a given spot on your body will be sensitive to the tiny electric current. Of course it's less convenient to zap these areas where the skin is less sensitive, and more convenient to zap more sensitive areas, like the belly, chest, thighs, arms, etc. Just be prepared to slightly move the zapper every few seconds or minutes as needed. Often times one will only need to move the zapper an inch
or two to minimize the electric tingle. Perhaps you would be best to start off by zapping the bottom of a foot where it is not likely you will ever feel the electricity to any great extent.