A SARM is a class of compound that can bind to the androgen receptor, but is not actually a steroid hormone
Our SARMs are non-steroidal molecules that target and modulate the activity of androgen receptors within the cell on the nuclear membrane. The SARM binds to the androgen receptor, and then can interact with a receptor-specific segment of DNA that controls gene expression. The binding of a SARM with its nuclear hormone receptor can either activate or inhibit the nuclear activity because it can either block or stimulate the same nuclear hormone receptor under different conditions.
SARMs have the beneficial effects of natural androgen hormones, while minimizing the undesirable side effects
Natural steroidal hormones (testosterone, estrogens, glucocorticoids, etc.) are biologically active in their normal hormone pathways, and as such their use has often been limited by undesirable side effects. GTx designed its SARMs to produce the beneficial effects of natural androgen hormones, while minimizing the undesirable side effects.
The metabolism of natural steroids involves chemical reactions that change these molecules into other related molecules. This is one cause of the undesirable side effects that can be circumvented by treatment with GTx SARMs. Several enzymes (such as CYP19 aromatase and 5-alpha-reductase) are present in the body to convert androgen hormones to other hormones, including estrogen. Because these converted hormones control different bodily systems, it is easy to see that using androgens to target a bodily system specific to that androgen can inadvertently affect other systems.