Testosterone will not negatively affect collagen production. Various studies attest that it actually improves collagen synthesis, while others say it had only minimal or no affect on collagen at all. None of them ever mention testosterone negatively affecting collagen production however. Also, the amount of testosterone increase from exercise is low in the grand scheme of things, so honestly I wouldn\'t bat an eyelid at it. Also, realize that exercise tears tissue down, and stimulates the rebuilding process. That\'s how our body works. Also, I\'m unaware of a study that conclusively states any supplement (other than anabolic androgenic steroids or similar growth factors) actually has a marked and proven increase on collagen synthesis. It\'s pretty much controlled by diet, genetics, and environment (pollutants, toxins, etc.) I agree with M7 on the things that will negatively impact collagen.