Testolone (RAD140) is a selective androgen receptor modulator (SARM) currently under development by Radius Health Inc. The intent of RAD140 is to serve as an alternative to testosterone replacement therapy. In the body, a normal dose of RAD140 mimics the effects of a LARGE DOSE of testosterone in muscle tissue but expresses a minimal affinity for non-muscular tissue. This results in substantially fewer undesirable side effects when compared with traditional anabolic steroids.

Clinical Uses
Provides anabolic support to test subjects with low testosterone levels (i.e. due to health issues, or prior abuse of anabolic steroids).

The bridge between anabolic steroid cycles. RAD140 is ideal to administer in between anabolic steroid cycles. After running PCT, RAD140 can be used to maintain muscle mass while the subject recovers and prepares for the next anabolic cycle.

Those who want to use a performance-enhancing drug, but are deterred by the negative side effects of running traditional anabolics.

Male subjects sensitive to gynecomastia. While RAD140 may produce effects similar to testosterone, it CANNOT aromatize to estrogen, therefore it can be used without fear of “gyno”, “man boobs”, or bloating.
Negative Side Effects:

As of this writing, RAD140 trials have shown an absence of side-effects normally associated with anabolics. Specifically, estrogen, progesterone, and prolactin-related side effects are ZERO.

Regarding HPG/HPTA suppression: All SARMs will exhibit a degree of suppression, and RAD140 is no exception. The key word here is suppression. Traditional anabolics don’t just suppress, they cause a complete shutdown. While some researchers dispute the ratio of LH/FSH/Testosterone suppression caused by SARMs, the bottom line is: SARMs suppress endogenous hormone production to a much lesser degree than traditional anabolics, making recovery MUCH faster. While we don’t necessarily recommend it as an optimal approach, many researchers opt to skip PCT for SARMs-only cycles.