There are two effects of testosterone: androgenic and anabolic. Androgenic effect (masculinity) is manifested in the development of secondary male sex characteristics - growth and body structure - narrow hips, broad shoulders, men's facial features, less fatty layer, hair on the face, low voice, typical for men libido, aggressiveness in behavior and etc.
The anabolic effect is due primarily to the enhanced growth of muscle tissue. Speaking about the anabolic steroid with a clear emphasis on the first word, mean, first, the desirability of this effect, and, secondly, as if in opposition to the term "androgynous" to emphasize that the steroid by changing the molecular structure of testosterone attempt enhance the function of the impact on growth of tissue and slow down function enhance secondary sexual characteristics. It should be noted that drugs that have fully complied with these requirements, yet failed to create, and almost all anabolic steroids have a pronounced androgenic effect.
Molecule natural testosterone is artificially modified for the purpose of giving the properties to be absorbed by the body more slowly to prolong the anabolic effect. It is known that if to take a dose of pure testosterone, the result of natural metabolic processes it will be quickly removed from the body by the liver, not having to exert any noticeable effect on muscle tissue and other processes, such as for increasing endurance when performing physical work. To achieve anabolic effect of the drug should "linger" in the body several times to pass through the bloodstream before it is removed from the body. This trying to accomplish by weight of molecules, introduction to the chemical structure of steroid additional radicals (number of chemical compounds), the use of different dosage forms of anabolic drugs. From the dosage form (tablet, capsule, oily solution for intramuscular injection, a suppository, etc.) depend on the duration of drug action and force of effect, and toxicity.
Once in the bloodstream, anabolic steroids bind to transport proteins and in this bound form travels to all organs. All steroids are poorly soluble in water and in lipids (fats). Therefore, they accumulate in the lipid structures of cell membranes and other fat depots, from which they can then for a long time to get involved in the bloodstream. To this effect and calculated the dosage form anabolic steroids in an oil solution. Therefore, if you apply steroid drugs in oil solutions, they will have the properties of a much longer impact on the body.
Enteral (via gastrointestinal tract) and parenteral (bypassing the gastrointestinal tract) the introduction is characterized in that in the first case the drug will pass through the liver and be exposed to its transformative enzymes that neutralize the action of steroids and in the second case will be able to bypass these systems, while the steroid will not make the "second circulation" circulatory system, and not meet with these systems transformation.
In the liver anabolic steroids undergo chemical modification and related compounds excreted in the urine. At this stage, and may detect the service specialists and anti-doping control.
You should know that tablet steroids quite toxic to the liver. Steroids intended for insertion into the body by injection, usually less toxic.
In the human body anabolic effect have also somatotropin (growth hormone - GH) and gonadotropin hormones by the pituitary gland. The first one acts directly on tissues and organs, the second increases the synthesis of endogenous testosterone in the body. Both banned for use in sport, the IOC MC.