Steroids are either injected intramuscularly or taken orally.When injected the substance directly enters the blood stream while tablets taken orally, reach the liver through the gastrointestinal tract.Here the substance is either completely or partially destroyed or sent into the blood stream in its original form.

The steroid is now present in the blood in the form of numerous steroid molecules which, through blood circulation, move around the entire body. Each steroid molecule contains a certain message or certain information which it tries to transmit to specific body cells.

The cells designated for this purpose possess various receptor types on their membranes.One of these is the steroid receptor which, for example, is present in large amounts at the muscle cell.

The form and size of these steroid receptors match those of the steroid molecules.Receptors and molecule show a high affinity,comparable to a key that fits the right lock.

The steroid receptor absorbs the matching molecule while rejecting thousands of other molecules which do not fit in size and shape.
The same is also true for the many other receptor types which cannot work with the steroid molecule since they are waiting for different molecules.

Only when the steroid receptor and the steroid molecule have formed a complex can the molecule transmit its message to the muscle cell.During this process it must be observed that the steroid molecules in the blood stream,to a large extent should have already previously bonded with binding proteins.Simplified, this means that usually close to 98% of the steroid molecules in the blood are bonded with binding proteins, while only 2% of the steroid molecules are present in a free and unbonded state.The latter form is also called the active steroid molecules since only these can form the steroid receptor complex.

The steroid molecules bonded to SHBG [ sex hormone binding globulin] are called the passive steroid molecules since, at this time and in this condition,they cannot be absorbed by the muscle cell and are therefore ineffective.It should be mentioned that the SHBG bonding behavior of some steroids is slightly different,so that the percentage figures can slightly differ.

The formed steroid receptor complex now travels to the cell nucleus where it bonds to certain sequences on the nucleic acid sections of the DNA (desoxy ribonuclean acid)Now a transcription takes place, where a template of the DNA is made. The resulting MRNA (messageger ribonnuclean acid) leaves the cell nucleus and bonds with the RNA in the cytoplasm (liquid cell part) where, through translation an increased protein synthesis takes place.

When combined with an intensive weight lifting workout , an increase in the diameter of the muscle cell occurs (muscular hypertrophy) .Although the increased protein synthesis is considered to be the most important effect of steroids on the muscle cell, the steroid molecules also forward other information which is important for atheletes.

There is increased evidence that steroids have a high anticatabolic effect. Thus, the rate at which protein in the muscle cell is broken down, is reduced.The steroid molecules occupy the cortisone receptors on the membrane of the muscle cell and block them.
Therefore, the cortisone produced by the body, a highly catabolic [reducing] hormone, cannot become effective and the muscle cell does not release protein.

Another advantage of steroids is that they increase the phosphocreatine synthesis (CP) in the muscle cell. CP is of crucial importance during the restoration of ATP.ATP is required for all muscle contractions since it is the fuel the muscles needs to enable it to work.
ATP is stored in the muscle cell and is changed into ADP (adenosine diphosphate) when needed.

This process releases energy, allowing the muscle to contract.To change ADP back to ATP,phosphocreatine (CP) is needed the more CP is needed.The more CP that is available, the faster ADP can be reconverted and the more ATP is thus available to the muscle.
In practice, this means that the muscle becomes stronger but not larger. For those who have tried the steroid oxandrolone you will have noticed that this compound, for the most part results in a strength gain . This is made possible since oxandrolone highly increases the phosphocreatine synthesis in the muscle cell.

Another factor which benefits the atheletes is that the steroids store more carbohydrates in the muscle cell in the form of glycogen.
This process together with a higher liquid retention which takes place simultaneously, results in a higher muscle volume, improved endurance, and more strength .

Steroids also reduce the release of endogenouis insulin since the steroids allow the muscle cell to absorb nutrients [ carbohydrates in the form of glucose and protein in the form of amino acids] by depending less on the insulin.This helps the athlete in lowering the body fat content and hardening the muscle since insulin, in addition to being a highly anabolic hormone, also converts glucose into glycerol and then triglyceride, thus stimulating the growth of the fat cells.

Those of you who have already taken steroids know that during training, a considerably improved pump effect in the respective muscles takes place, which by insiders is called 'steroid pump'.The reason for this is that steroids increase the blood volume and the amount of red blood cells in the body.The muscle has a larger appearance and becomes more vascular.

In addition to these advantages the increased blood flow calls for a greater transport of nutrients to the muscle cells.In particular, the highly androgenic steroids such as Dianabol ,testosterone and most of all Anadrol, cause a significant increase in the blood blood volume which sometimes results in an extreme pump during workouts.

The improved oxygen supply which results at the same time is often turned into an advantage by medium and long distance runners.

After the steroid receptor complex has done its job in the cell nucleus, the steroid molecule returns to the blood system and can either be reused briefly for the same purpose or changed into a weaker , ineffective molecule, which is then excreted through the urine.

Not all steroid molecules in the plasma (fluid portion of the blood)are, after exogenous administration, either directly bound to SHBG or present as free, active molecules. A certain portion can be immediately metabolized and eliminated by the body.

Another part, however can be converted into the female sex hormone estrogen.This is an aromatizing process and the term, at first, seems difficult to understand .

When taking a closer look at the structure of the male sex hormone testosterone and the female hormone estradiol it is noticed that both structures.The body can easily make the necessary structural changes on the molecule by using certain enzymes.

Certain steroid molecules, like parts of endogenous and exogenous testosterone, convert into dihydrotestosterone (DHT).
Although DHT shows a higher affinity to the receptors of the muscle cell than testosterone does - leading some experts to believe that DHT is more effective than testosterone - it also has a higher boding potential with the receptors of sebaceous glands and hair follicles.
It is interesting to note that DHT cannot be converted into estrogen. In the end, all these molecules are excreted as urine.