Anabolic steroids and testosterone

Testosterone is the body’s primary androgen and plays a key role in a wide range of physiological functions, including muscle development, fat metabolism, mood regulation, and sexual function. Anabolic steroids are synthetic derivatives of testosterone that have limited medical uses, but their misuse is associated with significant and sometimes permanent health risks.

Updated on 17 June 2026

Testosterone is the body’s most important androgen, or the so-called male hormone. Most of the testosterone in men is produced in the Leydig cells within the testes. In men, small quantities are also produced in the adrenal cortex and in peripheral tissues through the conversion of androstenedione. In the female body, the testosterone concentration is considerably lower than that in the male body. However, testosterone has important effects on the female body as well. In women, testosterone is produced in the ovaries and the adrenal cortex [1, 2]. The hormonal regulation of testosterone is maintained and regulated by the hypothalamic–pituitary–gonadal axis.

Androgens have androgenic, anabolic and psychological effects on the body. The androgenic effects include, among other things, penile growth, hair in various areas, and baldness while the anabolic affects include, among other things, the enlargement of the larynx, the thickening of the vocal cords, lipid changes, muscle growth, reduced fatty tissue, the enlargement of the sebaceous glands, and formation of blood cells. Androgens have psychological effects on the libido, virility, sexual behaviour, and aggressiveness [3]. Read more about testosterone, anabolic steroids and aggression

Anabolic steroids are synthetic derivatives of testosterone. With these, the field of medicine has sought to obtain the anabolic effect of testosterone without its virilizing adverse effects so that women and children could use anabolic steroids as well. These efforts have failed, however. For this reason, the term “anabolic steroid” is somewhat misleading. As a term, “anabolic androgenic steroid” is more accurate [4].

Testosterone is the body’s natural anabolic androgenic steroid. Testosterone and other anabolic steroids have the same basic chemical structure. There have been efforts to change the structure of synthetic anabolic steroids by increasing the anabolic effect and reducing the androgenic effect [5]. The anabolic-androgenic ratio of testosterone is 1:1 and both effects are strong. In the case of other anabolic steroids, this ratio varies so that the anabolic effect is greater [2, 6]. Furthermore, the anabolic steroid structure has been changed so that, for instance, administration, absorption, duration, and aromatization can be varied. So, the various anabolic steroids differ from one another by their androgenic ratio and administration (oral or intramuscular injection or dermal application), by their absorption time and duration of action, as well as whether they are aromatized into estrogens [7, 8].

History

The use of modern testosterone can be estimated to have begun in 1935 when testosterone was successfully isolated from bull testicles. Rather quickly, it was discovered that oral testosterone is hepatoxic and that it has a fast half-life. After testosterone was synthesized, injectable propionate entered the markets and, later in the 1950s, the longer acting enanthate. In the 1950s and the 1960s, the pharmaceutical industry grew more and more interested in new androgens and by the end of the 1980s countless anabolic steroids, had been developed [9, 10].

Mechanism of action

Testosterone and all anabolic steroids affect the body through the androgen receptors. The androgen receptors are located in the X chromosome of the cells and they are widely found in the body. Androgen receptors affect the muscles, but also the heart, immunity, and the nervous system, among other things [11].

The popularity of testosterone as a doping substance can be explained by its strong effect on muscular strength and mass. Testosterone also affects lipolysis, or the breakdown of fatty cells. Both short-term and long-term use of anabolic steroids lead to pronounced cell growth due to the added protein synthesis. The muscle cell growth induced by testosterone is stems from the activation of satellite cells and the growth of muscle cell nuclei [2].

The number of androgenic receptors is limited and typically the natural, normal levels of testosterone are sufficient to fill them. That is why a large number of additional anabolic steroids may not necessarily explain muscle growth. Another mechanism explaining muscle growth may be the effect of anabolic steroids on cortisol. Cortisol is a catabolic hormone and anabolic steroids may reduce its effect. The obstructive effect of anabolic steroids on the myostatin gene has also been suspected to be one of the mechanisms behind muscle growth. Myostatin regulates muscle growth [8]. Anabolic steroids also affect several other genes involved in muscle growth, including those that regulate metabolism, recovery, inflammation, and receptor expression. Therefore, anabolic steroids do not merely increase muscle mass; they can also alter the function of muscle cells at a deeper biological level. Some of these changes may be long-lasting. Testosterone also increases the secretion of growth hormone and insulin type of growth factor [12, 45].

Medical use

Anabolic-androgenic steroids (AAS) and testosterone are classified as prescription drugs permitted only for the treatment of diseases confirmed by the drug authorities. These diseases include, among other things, Testosterone Deficiency Syndrome (TDS) caused by the pituitary gland or testicles, different kinds of anemia, osteoporosis, and chronic diseases of protein deficiency and prolonged tissue healing. Testosterone is also used for the treatment of male menopause symptoms. Prescription testosterone use has increased considerably both in Finland and globally during the last couple of decades [13, 14, 15].

Testosterone is used as injections of various testosterone esters (for example, testosterone propionate, testosterone enanthate, testosterone phenylpropionate, testosterone isocaproate, testosterone decanoate, and testosterone undecanoate) or as testosterone undecanoate capsules, taken orally. Anabolic steroids are available both as injections and capsules.

Use for doping purposes

Both testosterone and anabolic steroids are doping substances under the Criminal Code. They are the most popular doping substances.

For example, the following substances are sold illegally online and elsewhere on the black market (well-known trade names given in parentheses):

• Nandrolone (Deca-Durabolin, Retabolin, Laurobolin),
• Metandienone (Dianabol, Danabol, Anabol, Metabolin),
• Stanotzolol (Stromba, Winstrol, Winstrol Depot),
• Trenbolone (Parabolan, Finajet),
• Oxymetholone (Anapolon, Anadrol, Androlic),
• Oxsandrolone (Anavar),
• Boldenone (Equipose),
• Fluoxymetsterone (Halotestin),
• Metenolone (Primobolan, Primobolan Depot),
• Testosterone and derivatives (Sustanon, Panteston).

The main purpose of using these substances is to acquire a larger and better, more muscular appearance. Naturally, the fast results and slowdown in the development of muscle growth may act as motives for use. Improving sports results is the motive of people engaged in strength sports.  Other motives include increasing the workout output, burning fat, slowing down ageing-related changes, and improving self-confidence and mood, among other things [8, 16, 17, 18, 19, 20].

Anabolic steroids are often used intermittently. The periods of use last from a few weeks to even years, but on average a few months. Often between the periods of use, breaks lasting a few months are taken. At the beginning of a period of use, the quantity of steroids is gradually increased and, toward the end of the period, steroid use is discontinued in steps over a period of one to two weeks. The purpose of the breaks is to reduce the adverse effects and to give the body’s hormone production time to recuperate. Another method of use is the so-called blast and cruise. The blast and cruise regimen involves the alternating use of higher (blast) and lower (cruise) doses. During a blast and cruise period, the use is continuous and no breaks are taken. Abuse is characterized by the excessive use of anabolic steroids and several different kinds of anabolic steroids at the same time (stacking) [8, 16, 17, 20, 21]. Oral anabolic steroids are used daily because of their fast half-life. Intramuscular anabolic steroids are often used weekly [22].

Medical anabolic steroid use seeks to attain the body’s physiological concentrations, but use for doping purposes often seeks concentrations that are multiple times higher (supraphysiological levels) [8].

Adverse effects

Since androgen receptors are widely found in the body, anabolic steroids affect the function of a number of different organs. This is why there are a number of potential adverse effects as well. Some of these effects are mild and temporary while others are life-threatening. The risk of adverse effects grows with the long-term use of high doses.

There are a number of things that complicate the processes of studying the adverse effects of anabolic-androgenic steroids and obtaining scientific evidence. Firstly, the use of anabolic steroids is illegal in a number of countries, whereupon people are unlikely to say anything about anabolic steroid use. Secondly, because the substances are acquired on the black markets, users do not necessarily know what substances they are using or in what quantities. Thirdly, the adverse effects of high doses cannot be the subjects of experiments on humans for ethical reasons. Finally, people also abuse substances intended for veterinary purposes, but no research data exists about the effects of these substances on humans. It is also common for anabolic steroid users to use multiple other performance-enhancing substances and dietary supplements simultaneously. In addition, competitive bodybuilding is associated with several other risk factors, such as extremely intensive training, high protein intake, and significant fluctuations in body weight. These are the reasons why the research data is largely speculative, often based on case studies and experiments using medical doses [8, 46].

According to a Finnish population-based study, the risk of anabolic steroid and testosterone abusers dying prematurely was 4.6 times higher than in the control group [23]. In a similar Danish study, the mortality rate of anabolic steroid users was three times higher than in the control group over a period of seven years. The users also made considerably more hospital visits [24]. The most common cause of premature death among anabolic steroid users is cardiac-related death [47].

Not all anabolic steroid users experience serious adverse effects, and the effects are not the same for everyone. However, because there are many potential side effects, nearly every user experiences some form of harm either during use or after discontinuation. The most common adverse effects include fluid retention, irritability, acne, and gynecomastia. A decrease in libido after a steroid cycle is also very common. [48]

Adverse effects: hormonal disturbances

When excessive levels of testosterone or anabolic steroids are introduced to the body, they induce hormonal and reproductive health disturbances.

In men, this suppresses endogenous hormone production. Structural shrinking takes place in the hormone producing glands and organs, such as the testicles. The periods of abuse are followed by infertility and weakened sexual functions [25, 26]. These changes are often reversible, but they can last for years. Sometimes the body will not recover at all.

As a result of use, men may experience chest pain and gynecomastia. This is because the testosterone and some of the anabolic steroids are aromatized into estrogen [27, 28, 29].

In female users, testosterone and anabolic steroids induce the excessive growth of body hair, the lowering of the voice, reduction in breast size, balding, the enlargement of the clitoris, skin problems, and menstrual cycle disturbances. Some of these changes may be permanent [25]. Read more about special characteristics of doping in women.

In adolescents, growth may stop, leading to short stature [25]. Anabolic steroid use at this age may be more damaging than use that begins in adulthood [30]. Read more about doping substance use among young people.

Adverse effects: severe diseases

When used in excessive doses, both testosterone and anabolic steroids cause harmful changes in cholesterol levels. A reduction in HDL cholesterol, often referred to as “good” cholesterol, is particularly common. Oral anabolic steroids tend to have a more pronounced negative effect on cholesterol levels than injectable preparations. They also have effects on blood coagulation factors, hemoglobin and blood pressure, among other things. Thus, the continuous use of these hormones will increase the risk of developing heart and vascular diseases, cerebral infarction or stroke. Steroids weaken the cardiac contractile force and induce cardiac muscle degeneration, which can lead to cardiac arrhythmia and sudden death [31, 32, 33, 34, 48].

The exacerbating effect of anabolic steroids and testosterone on diabetes has been known for a long time. The use of these substances increases insulin resistance and the risk of diabetes and it may induce prediabetes [35]. The sharing of syringes with other users may cause a blood-transmitted disease, such as hepatitis or HIV [36].

The excessive use of testosterone and anabolic steroids also increases the risk of liver damage and cancer [16, 37]. Anabolic steroids that are administered orally are more harmful to the liver than those that are injected. Liver diseases vary from reversible, slight cell damage and jaundice to malignant liver tumours with a bad prognosis even when treated. The direct harmful effects of anabolic steroids on the kidneys remain uncertain. However, their indirect effects through elevated blood pressure may pose a risk to kidney health. [48] Read more about anabolic steroids dependence.

Adverse effects: mental disorders

Testosterone and anabolic steroids also affect the central nervous system. Their sites of action within the brain are closely connected to the centers that regulate mood, sexuality, and aggressiveness [38].

About 20 to 30 percent of the people who use excessive doses of testosterone and anabolic steroids have obvious mood disorders during the period of use. These disorders meet the criteria of the psychiatric disease classification and they include depression, anxiety, psychotic reactions with hallucinations, hypomania, and weakened level of cognitive performance [8, 25, 31]. It is also estimated that about one-third of anabolic steroid users experience anabolic steroid addiction [39, 40].

About 30 percent of the people who use excessive doses of testosterone and anabolic steroids are aggressive, hostile, and irritated during the intake period. Based on a number of case reports, hormones weaken impulse control [31].

The mood disorders and behavioural changes are likely to be the sum of many factors. The high quantities of anabolic steroids are one explanatory factor, but the user’s personality and psycho-social environment also affect the behaviour caused by anabolic steroid use. For example, there is no strong evidence pointing to the so-called roid rage. Aggressive and violent behaviour has often been linked to other intoxicants in addition to anabolic steroids, as well as to susceptibility to other risk behaviours. However, anabolic steroids may act as the trigger [29, 41, 42, 43, 44].

Discontinuation of Use

At present, there is no clearly established evidence-based method for discontinuing the use of anabolic steroids.

The use of testosterone and anabolic steroids suppresses the body’s natural testosterone production and sperm production through negative feedback on the hypothalamic–pituitary–gonadal (HPG) axis. This effect may persist for a long time after discontinuation. Recovery of normal hormonal function varies between individuals. Studies have shown that hormonal function returns to normal within 3–6 months, and at the latest within one year, for most users. However, some individuals continue to have low testosterone levels for a longer period, and permanent reductions in testosterone levels have also been reported. The likelihood of recovery decreases with longer durations of use, older age, and the use of multiple anabolic steroids simultaneously [48, 50, 51].

Many users attempt to accelerate recovery through so-called post-cycle therapy (PCT). PCT typically involves the use of selective estrogen receptor modulators (SERMs), aromatase inhibitors, and human chorionic gonadotropin (hCG). These agents are intended to reduce estrogen-mediated negative feedback or stimulate testosterone production in the testes. Although such medications may temporarily increase testosterone levels, they do not necessarily address the underlying problem. For example, one study found no major difference in testosterone recovery between individuals who used PCT and those who did not. Most participants recovered to near-baseline testosterone levels within three months [48, 49]. In another study, only half of former users achieved hormonal recovery within three years. In that study, PCT appeared to accelerate recovery, but only when anabolic steroid use had been discontinued less than three months earlier [50]. The risks and effectiveness of PCT are also influenced by the poor quality and uncertain contents of products obtained from the black market [52].

Timo Seppälä
Medical Director
Finnish Center for Integrity in Sports FINCIS (previously the Finnish Antidoping Agency FINADA)

Updated by Dopinglinkki