Do steroids cause muscle and body growth? There is no evidence that ultra-high doses of steroids alone will cause muscle growth through a chemical effect. In many animal species, high doses of anabolic steroids produce no more muscle growth than the normal dose would.(1,2) However, there is evidence that steroids enhance muscle growth if taken along with rigorous physical training and a high protein diet.(3-5) This exercise program must be in place before and during anabolic steroid administration.(4,6)
Anabolic steroids act on the balance between anabolic and catabolic processes within the body. Anabolism is the constructive process by which simple substances are converted to more complex compounds, such as bone and muscle tissue. Catabolism is the corresponding destructive process which breaks down these complex compounds for removal from the body. The normal body will attempt to maintain a balance between these two processes as they carry out tissue renewal and replacement.(7)
The state of anabolism and catabolism may be measured by evaluating the body's nitrogen balance. As Stedman's Medical Dictionary puts it: [Nitrogen balance is] the difference between total nitrogen ingested and the total nitrogen excreted by an organism. In an adult, presumably not growing, this should be zero at a given intake or above.(8) Anabolic steroids reverse the catabolic effect by increasing protein synthesis in skeletal muscle.(4,7) They are believed to diffuse into the cellular cytosol and bind to the androgen receptor. The newly formed receptor-steroid complex migrates to the nucleus, interacts with the DNA and initiates transcription. The production of RNA is then increased, causing an increased rate of protein synthesis. In this way, the use of these agents increases muscle size and strength.(7,9)
In order for the athlete to accumulate extra muscle mass, his or her body must temporarily be in a state of positive nitrogen balance: More nitrogen (as muscle mass) must come into the body than is lost. During strenuous exercise, the release of glucocorticosteroids throws the body into a negative nitrogen balance. After exercise, the body experiences a temporary state of positive nitrogen balance, during which new proteins are added to muscle tissue. Unless there is further exercise, the nitrogen balance returns to zero.
Without the use of anabolic steroids, muscle mass is built up very slowly after long periods of rigorous training. Anabolic steroids can reverse the short-term catabolic effect, leading to positive nitrogen balance and faster gains in muscle mass. However, maintenance of a positive nitrogen balance is short lived (1 - 2 months) unless the steroid dose is continually increased. Rapid tolerance (tachyphylaxis) to steroids occurs in muscle tissue as the body attempts to maintain homeostasis.(9)
One homeostatic mechanism may be a rise in serum cortisol during steroid treatment. This may counteract the anabolic effect while potentiating the catabolic.(9) The risk of serious side effects is increased as the athlete takes higher and higher doses of anabolics to maintain a positive nitrogen balance.
There is some evidence that anabolic steroids cause the athlete to feel like working out more often and more vigorously.(5) This psychological effect may be more important than any direct chemical effect.(5) Frequent and more vigorous workouts may be a reason for the increased incidence of connective tissue injuries associated with steroid abuse.(10)
1. Wilson JD. Androgen abuse by athletes. Endocrine Reviews 1988;9(2):181-99.
2. Strauss RH. Anabolic steroids. In: ed. Drugs and Performance in Sports. Philadelphia: WB Saunders, 1987:5, 59-67.
3. Wagner JC. Abuse of drugs used to enhance athletic performance. American Journal Of Hospital Pharmacy 1989 Oct;46:2059-67.
4. Kibble MW, Ross MB. Adverse effects of anabolic steroids in athletes. Clinical Pharmacy 1987 Sep;6:686-92.
5. Kleiner SM. Performance-enhancing aids in sport - health consequences and nutritional alternatives. J Amer Coll Nutr 1991 Apr;10(2):163-76.
6. Daigle RD. Anabolic steroids. J Psychoactive Drugs 1990 Jan- Mar;22(1):77-80.
7. Smith DA, Perry PJ. The efficacy of ergogenic agents in athletic competition. part 1: androgenic-anabolic steroids. Annals Pharmacother 1992 Apr;26:520-8.
8. Stedman TL. Stedman's Medical Dictionary. Baltimore: Williams and Wilkins, 1976.
9. Windsor R, Dumitru D. Prevalence of anabolic steroid use by male and female adolescents. Med Sci Sports Exercise 1989 Oct;21(5):494-7.
10. Yesalis CE, Wright JE, Bahrke MS. Epidemiological and policy issues in the measurement of the long term health effects of anabolic-androgenic steroids. Sports Medicine 1989 Sep;8(3):129-38.
Return to Nutrition and Weightlifting Page