d) Reduction of SHBG:
An important mechanism of action of some anabolic steroids often ignored by most users, is in its ability to reduce levels of SHBG (Sex Hormone Binding Globulin). Testosterone unbound (free) has biological activity while bound to SHBG is inactive. The SHBG acts as a modulator of secretion androgenic in tissues. Thus, lower levels of SHBG increases the availability of androgen action, since they fail to bind thereto. So if you do only one testosterone cycle and SHBG levels are high you lose effectiveness of steroids cycle, since part of the testosterone will bind to SHBG. You can increase the efficiency of the cycle added a drug that reduces SHBG, and other additional effects of the drug logically. Examples of steroids that significantly reduce SHBG: stanozolol, Turinabol, proviron, anadrol.