Enobosarm is the generic name of an investigational selective androgen receptor modulator. Also known as Ostarine, it was first developed for the purpose of increasing muscle mass and bone density. This is particularly helpful for those handicapped by debilitating diseases—it was a new alternative over those steroids which have benefits that cannot surmount the heap of undesirable side effects they simultaneously bring. Since it affects both bone and muscle, Ostarine is used for treating osteoporosis, osteopenia, muscle sarcopenia, cachexia in cancer patients, and even andropause. But what is the science behind Enobosarm?
Selective receptor modulators are drugs that affect tissue types differently—for instance, a selective receptor modulator may be beneficial for one tissue type while being an antagonist to another. As a selective androgen receptor, it has the same effects as other androgenic drugs like anabolic steroids—but more selective in terms of impact, as previously mentioned. The selectiveness in terms of effect—since the modulator discriminates according to tissue type—also allows it to be used in many more circumstances as compared to anabolic steroids, which have limited legitimate usage.
The androgens that are usually used—for instance, in case of male hormone replacement therapy—are injectable or in-skin delivery formulations. However, injectable forms are known to spike testosterone levels in blood, excessively increasing first and then leveling down drastically afterward. Skin delivery formulations, on the other hand, allow a more acceptable testosterone blood level profile. With selective androgen receptor modulators like Enobosarm, the goal is to customize tissue response. After oral ingestion, the selective androgen receptor modulator would elicit a response from target tissues in the same way these would respond to testosterone, without the risk of side effects for healthy, non-targeted tissues.
This goal, while already achieved at some level, has not been fully perfected. Selective androgen receptor modulators targeted at muscle or bone still cannot operate without creating androgenic effects on some tissues, like the prostate gland. However, even if selective androgen receptor modulators unavoidably create virilizing effects in high doses, they have been proven to be considerably selective in application for anabolic effects provided they are administered in low dosages. This is crucial especially if the modulators will be utilized to treat osteoporosis in women.
For example, Ostarine can be used to build and maintain lean muscle mass. Ostarine binds with the androgen receptor and then demonstrates osteo-anabolic and myo-anabolic activity. Once the androgen receptor is activated, gene expression is altered, thus increasing protein synthesis. This equates to more muscle mass. In this aspect, Ostarine works in a similar manner as steroids. The key difference, however, is that it does not foster the same growth effect on prostate and secondary sexual organs. Some of the most recent formulations of selective androgen receptor modulators almost exclusively have anabolic effects on muscle tissue.
The mechanics of the selectivity of Ostarine can also be described according to gender. For instance, when used in bone growth for males in cases of osteoporosis or osteopenia, the prostate and testes will be minimally affected, if at all. For females, selective androgen receptor modulators can be used for bone retention, and the stimulation of libido and other androgen-influenced sexual functions without the side effects of virilization—the development of male gender characteristics—increased cholesterol levels, and liver dysfunction, among others.
Furthermore, one of the great breakthroughs made by selective androgen receptor modulators like Enobosarm is that the molecules can now be administered orally. This is a substantial improvement over the anabolic steroid alternative. Most anabolic steroids are not active orally and are injectable. Those that are not orally active have a great tendency to cause liver damage, depending on the dosage.