I just read that Andrgogel uses "bio-identical" testosterone. I think that means that it was naturally derived from yams, as opposed to manufactured synthetically, but I'm not sure. In any event, I was wondering if anyone knew whether bio-identical testosterone was easier on the body or provided any other benefits over synthetic testosterone. I just switched from androgel (which uses bio-identical testosterone) to a cream (which uses testosterone of an unknown type) and I feel noticeably lousier and sometimes flushed. My estrogen and test levels just came back and are fine (to my surprise), so perhaps my symptoms have nothing to do with TRT.