BS
NAC, N-acetyl cysteine is an acety-bonded form of the non-essential amino acid cysteine, and its only stable form since pure cysteine readily converts to cystine.
First of all any literature on the beneficial effects of NAC are limited to its medical use in inhalers and powders as a broncho-dilator and in its use in combination with target-specific anti-biotics for the treatment of bronchitis.
As far as the physiology goes I think its important that anyone thinking of using it knows that it readily excretes zinc, copper and iron from the body, three minerals that have deeper inherent anabolic properties than NAC itself. Its also important to remember that as an athlete you most likely already are deficient in zinc and maybe iron.