Prohormones are substances which are precursors of the hormones, while they do not have biological activity by themselves. The term of “prohormones” was first time used in medicine in the middle of the 20th century. In human body there are large number of natural prohormones: proinsulin is the precursor of insulin, thyroxine is the precursor of triiodothyronine, and others.

In bodybuilding under the term of “prohormones” prosteroids that entering the body usually convert by enzymatic cleavage of the molecule into the active anabolic steroids such as testosterone and others are understood. Although the terms of “prohormones” and “prosteroids” are not synonymous, as many believe. Prosteroids are just one of the types of prohormones.

Since 2011 prohormones have almost disappeared from the market of sports nutrition, due to the massive import ban in Russia, as well as their production.

Prohormones in bodybuilding

In the past two decades, prohormones (prosteroids) are widely used by athletes in bodybuilding, powerlifting and other power kinds of sport to increase a muscle mass and power indicators. Initially, the main advantage of prohormones was their legal status, because officially they are not belonged to the category of anabolic steroids. Nevertheless, in recent years, many pro-hormones are included in the list together with steroids and their turnover is limited.

Today, manufacturers are constantly working on new prohormones, which are not yet included in the list of prohibited, however in one-two years the product is usually withdrawn from circulation. Thus, there is a constant race of companies and the State with a lag of the last for some time.

Usually manufacturers declare that their prohormones much safer than steroids, but in reality this is not always true. Firstly, the main purpose of the manufacturer is not the creation of a safe product, but the synthesis of a new formula, which would have anabolic effects and not be placed to the list of prohibited, while the issue of security goes by the wayside. Secondly, most prohormones are much weaker than anabolic steroids, and this explains the lower incidence of side effects. Here it can be concluded that prohormones not more safe than steroids in moderate doses.

Permanent race of manufacturer and the State control leads to the emergence on the market of prohormones that do not pass any clinical trials, and often it turns out that these supplements have some serious side effects that are more severe than the classic steroids. It must be noted that the status of prohormones are food additives, which means that the control of the quality of these products is much lower than of the pharmaceuticals.


Prohormones have no pharmacological advantages over the anabolic steroids and usually much weaker than they, while the side effects are often appears due to the low quality control and almost complete lack of research. There is a possibility of delayed adverse events, potential carcinogenic activity and etc.

Popular prohormones


  • Is converted to testosterone;
  • Studies show that the conversion rate does not exceed 6%, which means that only a twentieth part of the additive is converted to testosterone;
  • The high level of flavoring which means that there is the probability of developing a gynecomastia, an edema and other side effects;
  • High-androgenic activity.

4-androstenediol (4-AD)

  • Is converted to testosterone;
  • The conversion level is 15.76%;
  • Is not converted into estrogens;
  • Has less androgenic activity compared to the 4-androstenedione, because does not turn into degidrostestosteron.


  • Is converted to nandrolone (retabolil);
  • Anabolic activity is almost like testosterone’s;
  • Is not converted into estrogen;
  • Low androgenic activity.


  • Is converted well as to nandrolone;
  • The conversion level is a little higher than the previous prohormone.

1-androstenediol (1-AD)

  • Is converted into 1-testosterone (dihydroboldenone);
  • Has a 7-fold greater anabolic activity, and 2 times more androgenic activity than testosterone;
  • Is almost completely converted to the active form passing through the liver;
  • Is not flavored (not converted into estrogen).

1,4-androstadienedione (1,4 AD)

  • Is converted to boldenone;
  • High bioavailability upon oral administration;
  • Low degree of aromatization to estrogens (50% lower compared to testosterone);
  • Low androgenic activity.

1-testosterone (T-1)

  • Similar to testosterone;
  • Has a 4-fold greater bioavailability upon oral administration compared with testosterone;
  • Is not converted into estrogen;
  • In fact it is not a prohormone.

Side effects

Prohormones have the same side effects as anabolic steroids. Intensity and frequency depends on the particular formulation additives. Many prohormones requires the “Post Cycle Therapy”.

Scientific review

The testosterone and the growth hormone are the main hormones in terms of muscle growth (anabolic processes), increased muscle strength, slowing catabolic reactions, reducing the proportion of fat in the body. Moreover, testosterone is responsible for some male characteristics (such as hairiness of certain parts of the body, rough voice, etc.). It is widely known that athletes often take large doses of anabolic steroids to improve adaptation to training, increase muscle mass and / or accelerate the recovery during intense workouts.

Studies have generally shown that taking anabolic steroids and growth hormones actually contributes to the increase of muscle mass and power. Nevertheless, such practice has a number of side effects. There are cases of a hormonal dysfunction, disorders of the liver, a hyperlipidemia (increased levels of lipoproteins in the blood). In addition, taking the steroids increases the risk of cardiovascular disease and inadequate behavior (the so-called "steroid rage"). Some of these effects are irreversible, especially in women. For this reason, the majority of sports organizations banned the use of anabolic steroids. The using of them must be avoided.