Actually it makes chlorine dioxide when activated, which is different from chlorine. In fact, the body manufactures its own chlorine dioxide as a cleansing agent.
There are no studies regarding the internal use of chlorine dioxide, and there never will be any. Thousands upon thousands of people have used it, with nothing but positive effects, but there are no "studies", double blind or otherwise.
You are going to have to just research the subjective information on it, and make your own decision whether it is for you or not.
I have used it myself, in a low dosage, for 4 years, and I personally know of many hundreds who have used it also.