Please notice: Everything written below on side-effects of anabolic steroids is only related to post-pubertal age-group. Anabolic steroids can lead to irreversible damage if taken before or during puberty!
We know pretty little about the impact of anabolic steroids used in high doses (for improved athletic performance and muscle growth) on human health. There are some well established facts, known to both athletes (at least the informed ones) and medical professionals. Among these is the inhibition of natural testosterone production through negative feedback (the mechanism is simple: if human body spots high testosterone levels, it signals to testosterone-producing organs to stop more production – this is the common way our other hormones work, too) with all its consequences like temporary testicular atrophy and infertility, which usually goes hand-in-hand with estrogenic effects on male body (like breast enlargement, as testosterone is metabolized to estradiol naturally).
Another well-known side-effect is liver damage by oral steroids. This can include almost every kind of damage, often serious (including carcinoma), depending on the extent of steroid abuse.
Most steroid-users will tell you that testosterone inhibition is reversible (it seems it indeed is, although there are reports of irreversible damage too) and can be dealt with by taking steroids in cycles and by use of ancillary medicaments restoring the natural testosterone production. As for liver damage, most athletes simply avoid oral steroids in favour of injectables (unless they need to be „clean“ soon after their cycle – I discus this issue elsewhere). If I say there is little scientific evidence for steroid impact on human health, I mean the claims of National Institute on Drug Abuse (NIDA) and others that steroids cause cardiovascular disease through: Increases in LDL (Low Density Lipoprotein, the „bad“ cholesterol) and decreases in HDL (High Density Lipoprotein, the „good“ cholesterol), high blood pressure, heart attacks and enlargement of heart´s left ventricle.
These are very serious claims, but are they proven? We have thousands of medical studies on cigarette smoking. Cigarettes are proven to cause heart disease and cancer beyond any doubt, yet they are legally sold. We are, however, lacking this kind of strong evidence regarding anabolic steroids.
Now, please don´t understand me wrong. I´m not saying steroids are safe to use, nor do I claim that you can avoid all the side-effects just by sticking to some principles like cycling and injecting the substance. All I want to say is that we need more research, and it is shocking so few scientists show interest in such a widespread group of medicaments.
On its official anti-steroid website (http://www.drugabuse.gov/PDF/RRSteroids.pdf) NIDA is listing 30 scientific papers on anabolic steroid abuse. The vast majority of them deal with psychological effects of steroids, steroid withdrawal and education (Intervention and prevention of steroid use in adolescents is one typical title). Only two are dealing directly with the question of what are the side-effects of steroids: Exposure to anabolic-androgenic steroids shortens life span of male mice and The cardiac toxicity of anabolic steroids. When you look at methods and scope of most papers (found elsewhere) you will be disappointed. Paper called Atrial fibrillation and anabolic steroids, for instance, is on „A young male bodybuilder, consuming large doses of anabolic steroids (AS), presented to the Emergency Department (ED) with symptomatic rapid atrial fibrillation“.
Just a short explanation to those not familiar with the established standards in medical trials: under normal circumstances we take two large (the larger the better) groups of people and follow their health over long period of time (the longer the better, again). One group is being administered placebo, the other one active substance which we study. Ideally, such trial should be double-blind, so that nor the patients, neither their doctors know (during the trial, not in its end of course) who is given placebo and who is given active substance, and of course conducted on humans, not mice or other animals. Considering the huge size of steroid-using public there should be no problem to conduct similar trials and I believe the athletes (at least non-professional) would be willing to cooperate if kept anonymous.
As for the long-term effects of anabolic steroids, today we have a large group of bodybuilders who started to use steroids in 1960´s and kept doing so over long periods of time. I never read a single paper studying their health (at least of those who didn´t become governors).
The list of suspected possible side-effects of anabolic steroids with references:
Santamarina R.D., Besocke A.G., Romano L.M., Ioli P.L., Gonoratzky S.E. Ischemic stroke related to anabolic abuse, Neurology Department, Hospital Privado de Comunidad, Mar del Plata, Argentina, Clinical Neuropharmacology 2008 (Describing a single case of 26-years old amateur athlete)
Huie M.J. An acute myocardial infarction occurring in an anabolic steroid user, Department of Human Biodynamics, University of California, Med Sci Sports Exerc. 1994 (Describing a single case of amateur weight trainer)
Tischler K.H., Heyny-von Haussen R., Mall G., Doenecke P. Coronary thrombosis and ectasia of coronary arteries after long-term use of anabolic steroids, Klinikum Darmstadt, Germany, Z Kardiol. 2003 (Describing a single case of a bodybuilder)
Stergiopoulos K., Brennan J.J., Mathews R., Setaro J.F., Kort S. Anabolic steroids, acute myocardial infarction and polycythemia: a case report and review of the literature, Division of Cardiovascular Medicine, Department of Internal Medicine, Stony Brook University Medical Center, Stony Brook, Vasc Health Risk Manag. 2008 (Describing a single case of an athlete)
Toyama M., Watanabe S., Kobayashi T., Iida K., Koseki S., Yamaguchi I., Sugishita Y. Two cases of acute myocardial infarction associated with a plastic anemia during treatment with anabolic steroids, Department of Internal Medicine, University of Tsukuba, Japan, Jpn Heart J. 1994 (Describing two cases of a 61-years old male and 59-years old female treated with anabolic steroids)
Negative changes in lipid levels
This is one of the few side-effects that can be considered proven I´m aware of three clinical trials (listed below) suggesting that Nandrolone decanoate (Deca-Durabolin) intake results in reversible lowering of HDL (High Density Lipoproteins).
Teruel J.L., Lasuncion M.A., Rivera M., Aguilera A., Ortega H., Tato A., Marcen R., Ortu J. Nandrolone decanoate reduces serum lipoprotein(a) concentrations in hemodialysis patients Servicio de Nefrologia, Hospital Ramy Cajal, Madrid, Spain, Am J Kidney Dis. 1997 (Study of 14 chronic hemodialysis patiens treated with Nandrolone Decanoate. Patients had lowered HDL)
Hartgens F., Rietjens G., Keizer H.A., Kuipers H., Wolffenbuttel B.H. Effects of androgenic-anabolic steroids on apolipoproteins and lipoprotein (a), Netherlands Centre for Doping Affairs, Capelle aan den Ijssel, The Netherlands, Br J Sports Med 2004 (Clinical trial with two groups: steroid users and control group. Steroid users had lowered HDL)
Baldo-Enzi G., Giada F., Zuliani G., Baroni L., Vitale E., Enzi G., Magnanini P., Fellin R. Lipid and apoprotein modifications in body builders during and after self-administration of anabolic steroids, Department of Internal Medicine, University of Padua, Italy, Metabolism 1990 (Comparison of 3 groups: bodybuilders using steroids, bodybuilders not using steroids and control group of non-sportsmen. Steroid users had lowered HDL.)
There is growing evidence that anabolic steroids can be addictive in some way. Several scientific papers have been published on this topic and this is a quote from one of them (Wood, R.I.): „In humans, it is difficult to separate the direct psychoactive effects of AAS from reinforcement due to their systemic anabolic effects. However, using conditioned place preference and self-administration, studies in animals have demonstrated that AAS are reinforcing in a context where athletic performance is irrelevant. Furthermore, AAS share brain sites of action and neurotransmitter systems in common with other drugs of abuse. In particular, recent evidence links AAS with opioids.
In humans, AAS abuse is associated with prescription opioid use. In animals, AAS overdose produces symptoms resembling opioid overdose, and AAS modify the activity of the endogenous opioid system.“ Translated into common language it means that anabolic steroids might be addictive as several facts point to such conclusion.
Wood R.I. Anabolic-androgenic steroid dependence? Insights from animals and humans. Department of Cell & Neurobiology, Keck School of Medicine of the University of Southern California, Los Angeles, Front Neuroendocrinol. 2008 (There are several other studies on this topic by the same author. Most describe developed animal addiction to testosterone)
The impact of Testosterone and other hormones on human behaviour and mood is well documented. Any treatment involving hormones or causing hormone imbalances is likely to result in mood changes, sometimes severe.
Anabolic steroids are known to suppress the coagulation factors (clotting factors) II, V, VII and X. This can cause higher tendency to bleeding in steroid users.
Until recently, it was widely believed that high testosterone intake can cause growth of benign and malignant prostate tissue (meaning it can cause prostate hypertrophy and cancer). According to a new, important paper published in 2009, this is apparently a wrong idea.
Jones, T.H. Advances in the Management of Testosterone Deficiency (Barnsley/Sheffield) (eds), Front Horm Res. Basel, Karger, 2009, vol 37, pp 197-203
Summary: Anabolic-androgenic steroids are a large group of medicaments with often very different effects and side-effects on human health. It is a well proven fact that certain anabolic-androgenic steroids can cause liver-disease if taken for longer periods of time. It is also most probable that some anabolic androgenic steroids can cause irreversible testosterone inhibition in males if taken for long periods of time, although this can be avoided (to some extent) by using steroids in cycles and using supportive medication. It seems to be most probable that some anabolic-androgenic steroids negatively influence the cholesterol levels in humans. More research is necessary to establish a connection between AAS and heart disease.
In other words: sausages and eggs influence the cholesterol much more than steroids. Cigarettes are most probably several times more dangerous to your heart. And fried food, as well as most oral medicaments, are liver-toxic. The most dangerous thing on using anabolic steroids is using them without proper professional advice, controlled drug-production and medical supervision. This is impossible unless the anabolic steroids are decriminalized.