It makes me sleepy immediatly after using it. But once that clears I feel more alert than usual. I think that being sleepy is a sign that something is being killed that shouldn't be there. After all the body still has to use up resources to clear out the junk. It can take weeks to thouroughly clean out parasites. And you would need to do it every day. It may also be that you have toxins that need to be cleared. When parasites die they release toxins.