Understanding anabolic steroids begins with grasping the mechanism of action of testosterone.
All anabolic steroids are synthetic or modified derivatives of testosterone.
Testosterone is produced in the Leydig cells of the testes and is referred to as an endogenous hormone.
When introduced from an external source, it is called exogenous.
Testosterone is metabolized into dihydrotestosterone (DHT) through the 5-alpha reductase enzyme, and into nandrolone during the process of its conversion to estrogen.
Therefore, testosterone can be considered the origin of all anabolic steroids.
Testosterone is the primary male sex hormone, acting as a chemical messenger that regulates various bodily functions.
The average testosterone production in men is 50-70 mg per week, which varies depending on genetics, age, and lifestyle habits.
During puberty, testosterone secretion peaks, triggering significant physiological changes in the body.
Testosterone regulates systemic functions and performs various roles, including muscle growth and tissue repair.
The Importance and Function of Testosterone in the Body
As the primary male sex hormone, testosterone is involved in the development and maintenance of male secondary sexual characteristics (voice deepening, body and facial hair growth, skin sebum secretion, sperm formation, libido, sexual function, and genital development).
All of these functions are known as androgenic effects, and without sufficient testosterone, they fail to develop or function normally.
The muscle-building effects are classified as anabolic effects, which are due to testosterone accelerating the rate of protein synthesis within muscles, thereby promoting muscle tissue growth.
This is why men tend to have more muscle mass and weigh more than women.
Men produce 2.5 to 11 mg of testosterone daily, while women produce only about 0.25 mg, which is one-tenth of the male level.
The primary female sex hormone is estrogen, which contributes to fat storage and women’s physiological roles, creating physical differences from men.
For example, women are generally shorter and have less muscle mass than men, and they experience bone degeneration more easily with age.
This is a result of the hormonal differences between men and women.
How Testosterone Specifically Works at the Cellular Level
Testosterone has complex and diverse effects throughout the body.
It travels through the bloodstream to target tissues, delivering messages to cells.
Key target tissues include muscles, skin, kidneys, bones, the nervous system, and the prostate.
Testosterone binds to androgen receptors located inside cells to regulate cellular activity, thereby producing effects such as protein synthesis, energy storage, and tissue growth.
This process is carried out by activating specific DNA sequences in the cell’s nucleus.
These processes occur slowly over several hours.
Unlike other hormones, testosterone is fat-soluble, allowing it to pass through the cell membrane to reach its receptor.
In contrast, peptide hormones interact with receptors on the cell membrane surface.
In muscle tissue, testosterone increases protein synthesis, and in the kidneys, it stimulates erythropoietin (EPO), boosting the number of red blood cells.
Additionally, it promotes lipolysis (fat breakdown) in fat cells and regulates sebum production and hair growth in tissues like the skin and hair follicles.
DHT, a metabolite of testosterone, exerts more potent androgenic actions in specific tissues.
Notably, hair loss requires a genetic predisposition; testosterone itself does not cause it but can accelerate its progression.
Medical Uses of Testosterone and Testosterone Replacement Therapy (TRT)
Testosterone and anabolic steroids are widely used to treat a variety of medical conditions.
Testosterone is effective in treating conditions such as male andropause and hypogonadism, female breast cancer, anemia, muscle-wasting diseases, osteoporosis, infertility, and syndromes like Turner’s and Klinefelter’s.
Testosterone Replacement Therapy (TRT) is for individuals with low testosterone due to aging or other factors, aiming to restore testosterone levels to a normal range and alleviate symptoms.
A normal testosterone level is typically defined as being between 350-850 ng/dl, and low levels can cause symptoms like decreased libido, reduced muscle strength, fatigue, depression, and bone weakness.
Testosterone positively impacts energy levels, muscle mass, bone density, and cardiovascular health.
TRT promotes a reduction in LDL cholesterol, helps regulate triglycerides, decreases body fat through lipolysis, and also improves insulin sensitivity.
Furthermore, its anti-inflammatory effects help reduce systemic inflammation.
However, TRT can have some side effects.
Older men, in particular, may have an increased risk of side effects such as benign prostatic hyperplasia (BPH) and elevated PSA levels.
It is recommended that individuals with a history of prostate cancer avoid TRT.
While research indicates that testosterone use has a positive impact on cardiovascular health, using supraphysiological doses can increase the risk of side effects, so it must be used under proper medical supervision.
Performance Enhancement and Other Non-Medical Uses of Testosterone
Testosterone was first used to enhance athletic performance and physique, but this use is not medically approved today.
This is due to political reasons related to ‘cheating’ in sports.
After the synthesis of testosterone in the 1930s, the potential for this substance to be used in various fields gained attention.
Dianabol, the first testosterone analog, was also designed for the purpose of performance enhancement.
However, its most widespread use globally today remains for improving athletic performance and physique.
Studies show that the majority of anabolic steroid users are not competitive athletes but rather middle-class, heterosexual men aged 25-35, who use them primarily for cosmetic purposes.
This contradicts the misconception that all steroid users are athletes.
When used at supraphysiological levels, testosterone is effective for rapidly increasing muscle size and strength, reducing body fat, and preserving muscle even in a caloric deficit.
It also helps to surpass genetic limits and increase muscle mass.
While there are various other non-medical uses, such as enhancing libido, the most common purpose remains the improvement of athletic performance and physique.
