Taken from
www.steroid.com/proviron.php;'Androgen Receptors are found in fat cells as well as muscle cells(5), and whilethey act on the AR in muscle cells to promote growth, they also act directly on the AR in fat cells to affect fat burning.(9)(3) The stronger the androgen binds to the A.R, the higher the lipolytic (fat burning) effect on adipose (fat)tissue(6)(2). As if that´s not enough good news, some steroids (notably, testosterone) even increase the numbers of A.R. in muscle and fat (9)(7). Thus, if you are taking a simple stack of proviron and testosterone, you´ll have more of the test you shoot as free testosterone floating around building muscle (compliments of the Proviron), more androgen receptors to be bound to (compliments of your testosterone) by your Proviron, thus causing more fat loss. Testosterone and Proviron are a very nice synergistic stack, pretty nearly an "ideal" stack of an oral and injectable, because both drugs will actually act to enhance the effect of the other.'