The use of anabolic steroids in sports

Based on a review of the literature and a careful analysis of the issues related to the ergogenic and adverse effects of anabolic steroids, the American College of Sports Medicine takes as its official position:

  1. Anabolic steroids, along with a proper diet, can contribute to increases in body weight, usually lean weight.
  2. Muscle strength gains obtained through high intensity exercise and an adequate diet can be increased by the use of anabolic steroids in some individuals.
  3. Anabolic steroids do not increase aerobic potency or the ability to maintain prolonged muscle exercise.
  4. Anabolic steroids have been associated with adverse effects on the liver, cardiovascular system, reproductive system and the psychological state in therapeutic studies and in more limited studies with athletes. Until more research is done, the potential deleterious effects of anabolic steroids on athletes should include all those found in the therapeutic studies.
  5. The use of anabolic steroids in athletes is contrary to the rules and ethical principles of a sports competition, as established by many of the institutions that run the various sports. The American College of Sports Medicine supports these ethical principles and repudiates the use of anabolic steroids by athletes.

This document is a review of the 1977 International Positioning of the American College of Sports Medicine on anabolic steroids.


In 1935 the already highly positive positive effect of androgens on protein anabolism was documented. This effect was later confirmed and the development of 19-nortestosterone was the precursor of steroid synthesis that has higher anabolic properties than natural testosterone, but less of its virilizing effect5. The use of androgenic steroids by athletes began in the early 1950s and increased over the years, despite warnings about their potential adverse effects and banning these substances by institutions who run sports.


Body Composition – Experimental studies in animals investigating the effect of anabolic steroids on body composition have demonstrated increases in lean body mass, nitrogen retention and muscle growth in castrated males and in normal females. The effects of anabolic steroids on the body weight of normal, untrained male animals, treadmill trained animals, rats with static training or monkeys submitted to strength training were minimal or absent; however, the effects of steroids on animals undergoing high intensity resistance training were not adequately studied. Male individuals with natural androgen deficiency due to castration or other causes had significant increases in nitrogen retention and muscle development with anabolic steroid therapy. Male and female subjects involved in experimental and therapeutic studies with anabolic steroids had body weight increases.

Most strength training studies in which body weight was reported showed greater weight gains under steroid treatment than with placebo. Other studies involving training did not report significant changes in body weight. In three studies that used the hydrostatic weighing technique, it was determined that weight gain occurred due to the increase in lean body mass. Four other studies did not find significant differences in lean body mass between steroid and placebo treatments but in two of these the mean differences favored steroid treatment. The extent to which fluid retention contributes to changes in body composition induced by steroids is a controversial issue which requires further investigation.

In summary, anabolic steroids can contribute to an increase in body weight at the expense of lean body mass. The amount of weight gained in studies involving training has been small but statistically significant.

Strength – Strength is an important factor in many sporting events. The literature on the efficacy of anabolic steroids for muscle strength development is controversial. Many factors contribute to the development of strength and we can include heredity, training intensity, diet and psychological status

In animal studies, the combination of anabolic steroids and overload training did not produce greater strength gains than those obtained only with training. However, steroid-induced gains have been reported in individuals undergoing weight training who are already experienced and inexperienced with and without control of diet or protein supplements. In contrast, no positive effect of steroids on strength gain over training alone was reported in other studies involving experienced individuals and inexperienced, without control of diet or protein supplements. Studies that did not report changes in strength with anabolic steroids were criticized for the use of inexperienced individuals in weight training, lack of diet control, low intensity training and non-specific assessment of strength. Studies that reported strength gains with the use of anabolic steroids were criticized for the inadequate number of individuals evaluated incorrect statistical analyzes, inadequate performance, and unsatisfactory reporting of experimental results.

There are no studies on the effects of massive doses of steroids used by some athletes over several years. Similarly, there are no studies on the use of anabolic steroids and training in women and children. Theoretically, the anabolic and androgenic effects would be greater in women and children, since these naturally have lower levels of androgens than the men.

There are three proposed mechanisms for the actions of anabolic steroids in increasing muscle strength:

  1. Increased protein synthesis at muscle level, as a direct action of the anabolic steroid.
  2. Blocking the catabolic effect of glucocorticoids after exercise, by increasing the amount of anabolic hormone available.
  3. Increased aggression induced by steroids, which provides better quantity and quality of strength training.

Despite the controversial and sometimes contradictory results of the studies on this subject, it can be concluded that the use of anabolic steroids, especially by individuals experienced in strength training, can provide gains in strength beyond those observed with training and diet alone. This positive effect is usually small and is obviously not observed in all individuals. The explanation for this variability of steroid effects remains unclear. When small increases in strength occur, these can be important in a sporting competition.

Aerobic power – The effect of anabolic steroids on aerobic power has also been questioned. The potential of these drugs to increase total blood volume and hemoglobin could suggest a positive effect of steroids on aerobic potency. However, only three studies showed positive effects and there was no confirmation of these results in subsequent studies. Thus, most of the evidence does not show positive effects of anabolic steroids on aerobic potency beyond what would be achieved through aerobic training alone.