Tibolone has tissue -selective estrogenic effects, with desirable effects in bone , the brain , and the vagina , and lack of undesirable action in the endometrium and breasts .  Its tissue selectivity is the result of metabolism , enzyme modulation (., of estrogen sulfatase and estrogen sulfotransferase ), and receptor modulation that vary in different target tissues, and differs mechanistically from that of selective estrogen receptor modulators (SERMs) such as tamoxifen , which produce their tissue selectivity via means of modulation of the ER.   As such, to distinguish it from SERMs, tibolone has been described as a "selective tissue estrogenic activity regulator" (STEAR),  and also as a "selective estrogen enzyme modulator" (SEEM). 
Many athletes, ball players, fighters, and any athlete who could benefit from the therapeutic relief often supplement with Deca Durabolin. Such individuals commonly have no desire to build any new lean muscle mass, but the relief alone is invaluable. Further, such relief can be obtained by a very low dose. A slightly higher dose will provide relief, greatly enhance overall recovery, and enhance muscular endurance. When it comes to performance enhancement, most athletes will find this steroid is hard to beat. More importantly, the relief effects of Deca Durabolin are not masking or false; this anabolic steroid shares nothing in common with over the counter painkillers or prescription painkillers like opiates. Such painkillers only mask the pain, whereas Deca Durabolin can actually heal the body.