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Most of us already know the following about anabolic steroids: they make muscles grow faster, they can have negative side effects and they are illegal to sell in Canada.
But how do they actually help bodybuilders pack on lean muscle mass?
Steroid metabolism
This refers to the entire set of reactions in someone who is producing or consuming steroids such as testosterone, oestrogen and progesterone to name a few. Testosterone is the male sex hormone and causes male characteristics to develop such as increased body hair, muscle growth and deepening of the voice. This is produced naturally in the testes. On the other hand progesterone and oestrogen are produced in the placenta in the ovary.
Artificial steroids including variations of testosterone such as Testosterone Propionate, Testosterone Cypionate and Testosterone Enanthate increase the levels of hormones in the body causing side effects such as muscle gain. There are three main phases of steroid metabolism and these are biosynthesis, genesis and catabolism/excretion.
Steroid Biosynthesis
Steroid biosynthesis is an anabolic pathway that creates steroids from simpler substances. In animals including humans, the biosynthesis of steroids follows the mevalonate pathway. This pathway begins with the molecule Acetyl-CoA and ends with dimethylallyl pyrophosphate (DMAPP) and isopentenyl pyrophosphate (IPP)
Steroidogenesis
Steroid hormones are derivatives of cholesterol that are synthesized mainly in the adrenal gland and the gonads. The main products of steroidogenesis are usually classified by endocrinologists into five groups of molecules:
- Glucocorticoids such as cortisol.
- Mineralocorticoids such as aldosterone.
- Androgens such as testosterone.
- Estrogens such as estrodiol and estrone.
- Progestogens such as progesterone.
The elimination of steroids is important in order to maintain hormonal balance in the body. Steroids are oxidised, which introduces oxygen to the steroid and in turn allows the cholesterol to be broken up by other enzymes into bile. These acids can then be removed from the body by being secreted from the liver in bile.
How anabolic steroids act
Anabolic steroids can be administered to the body in three main ways – oral tablets, skin patches and injection.
Taking steroids orally is arguably the easiest method of ingestion. However, the actual testosterone used at the end of the dose is about 1/6 of the administered level. This is because steroids are absorbed very fast when taken orally as opposed to the slower absorption when injecting or using patches. After the steroids are absorbed they are converted into useless metabolites, which are difficult for the liver to break down. As a result of this the amount of testosterone ingested has to be lower meaning that even lower amount of testosterone are actually available to act on the body. Oral steroids can cause liver issues such as cholestasis.
Skin patches provide doses of the anabolic steroid to the bloodstream at a slower rate than oral administration.
Due to the risk of liver damage from taking steroids orally, intramuscular injections tend to be the preferred method of taking steroids. By injecting steroids, they bypass the liver, which reduced the risk of liver damage.
Steroids work by entering the membrane of the cells that they are targeting. Once this has taken place the steroids then bind with the anabolic receptors of the cell, which are found in the cytoplasm (the main area of the cell body).
After this the steroids enter the nucleus of the cell by a process known as diffusion. The nucleus is a sort of brain for the cell that controls it and contains all its genetic makeup. Once the steroids have entered the nucleus, they start acting on the cell and bringing about hormonal changes that lead to effects such as increased muscle mass.
There are two main ways in which steroids increase muscle mass:
- They increase the rate of protein synthesis in the body so your body uses more protein up to produce more muscle.
- They stop catabolism taking place. In other words they stop muscles being broken down. This is useful as it inhibits the production of cortisol (the stress hormone), which leads to the body being less fatigued during a workout allowing you to train with greater intensity.