How Reversible Are Steroid Side Effects?

By William Llewellyn

Disturbed health markers, even in the short term, could reflect underlying damage to our health. There is still much question as to whether a substantial period of AAS misuse could lead to a greater incidence of disease or death years later.

Anabolic steroids tend to have side effects, especially when used at above therapeutic dosages. They can increase cholesterol, raise the hematocrit (“thickening” the blood), suppress natural testosterone production, and at least for oral varieties, impair liver function. Let’s not forget, too, those pesky cosmetic issues like acne, accelerated male pattern hair loss, and gynecomastia. Both sides of the steroid argument readily agree on this. Where there seems to be much disagreement, however, are the long-term risks of steroid use. Are steroid-related side effects reversible and if so, does a career of steroid use still increase the likelihood of disease or death later on? While science has yet to answer the latter question, the former has been the subject of much investigation. I’d like to review a study that looks at current and former steroid users, to see if side effects persist in both populations. As you will see, the results are both reassuring and concerning at the same time.


Before we get into the specific results, I think it is important to examine the protocols of the study. A total of 32 men participated in this investigation, each identified as a bodybuilder or powerlifer. About half of the men (15) were former anabolic steroid abusers, with an average age of 38. The amount of time since the men quit taking the drugs varied from one to 10 years, with an average of about 3.5 years. While they were using steroids, their average intake was 720 milligrams per week for 26 weeks per year over nine years. The other 17 men were current anabolic steroid abusers, with an average age of 30. They used an average of 750 milligrams per week for approximately 32 weeks per year over an eight-year period. The two groups in this study were fairly well balanced as far as history and usage patterns go, and seem to represent a formidable though fairly average history of anabolic steroid use at above therapeutic levels.

While they were using anabolic-androgenic steroids (AAS), each of the subjects self-administered without a medical prescription. According to a questionnaire filled out by the subjects, the most popular injectable agents of use were boldenone, drostanolone, formebolone, methenolone, nandrolone, stanozolol and various esters of testosterone such as testosterone enanthate and Sustanon 250. The orals most widely used included 4-chlorodehydromethyltestosterone (Oral Turinabol), fluoxymesterone, mesterolone, methenolone, methandrostenolone, oxymetholone, oxandrolone and stanozolol. Five ex-abusers and six current abusers had occasionally used human growth hormone (hGH) as part of their programs, at a dosage between 2 and 16 IU daily. Other non-steroid drugs commonly used by both groups included anti-estrogens and clenbuterol, as would be expected in such populations.

Lipids (Cholesterol)

Now let’s get to the results. To begin with, current steroid users noticed a predictable (negative) shift in cholesterol levels. In particular, HDL (good) cholesterol values were very low (< .9 nmol/L) in 15 out of 17 current AAS abusers. The cholesterol balance, of course, may reflect the ongoing disposition of plaque in the arteries during use. As such, a higher HDL level and HDL/LDL ratio are more desirable. After a minimum of one year of abstinence, the HDL level was below the normal range in only one ex-abuser. These results are in line with other short-term administration studies, as well as the common understanding of AAS, demonstrating a strong negative impact on serum cholesterol levels, and by extension cardiovascular disease risk, during the misuse of anabolic steroids. However, they also appear to support the reversibility of AAS-related changes in serum lipids, as no consistent (negative) findings were carried over into the lab results of ex-abusers.

Blood Cells

There were also distinct changes in the blood cell counts of current anabolic steroid users. In particular, there was a significant increase in hemoglobin (5%) and hematocrit (9%). These changes may reflect an increase in the oxygen-carrying capacity of the blood, and could improve performance. However, they may also represent an unwanted “thickening” of the blood by nature of increased red cell concentrations. This is very important because it can increase the likelihood of a cardiovascular event such as heart attack or stroke – especially in light of the other common health marker changes during AAS use, such as impaired cholesterol and elevated blood pressure. In the group of former steroid users, these changes in blood cell counts were not noticed. These findings support the position that there are distinct side effects on red blood cell counts during steroid use, but these changes are reversible when the drugs are discontinued.

Liver Enzymes

In the area of liver enzymes, there were notable changes in both groups. All of the current steroid users except one had elevated AST (aspartate transaminase) and ALT (alanine transaminase) values, which is often indicative of hepatic strain due to c-17 alpha alkylated (oral) anabolic steroid use. AST and ALT enzymes were elevated above normal in three and six of the former steroid abusers, respectively. The researchers discussed the potential elevation of liver enzyme values caused by exercise, and noted that both groups practiced strength training. However, changes in enzymes not related to exercise (such as GLDH) suggested the strain in current users was AAS-related. There were no signs of lasting impairment of the organ in either group upon ultrasound examination. These results are in line with numerous previous studies that show a risk of liver toxicity with current AAS misuse. However, they do not support the position that AAS misuse increases the long-term (post-administration) likelihood of hepatic health issues.

Hormone Levels

Testosterone levels were exceedingly high in steroid abusers, owing to the prominence of synthetic testosterone use in this group (the source was not natural but exogenous). This was accompanied by a severe suppression of gonadotropin levels, with LH and FSH levels lower by 91-94%. This reflects the underlying suppression of natural testosterone production in current steroid abusers. Unlike most of the other health markers, serum testosterone did not seem to recover to normal levels after AAS misuse. A troubling 13 of the former steroid abusers had testosterone levels that measured in the lowest 20% of the normal range for men. Two of the subjects had testosterone that measured below normal. The other hormones were within reference ranges for this group. While we generally like to view testosterone suppression during AAS use as a temporary side effect, it may not always be. If the results of this study hold true for the general population, it suggests that former steroid users are likely to struggle with sub-optimal testosterone production years after stopping use of the drugs. Therefore, this part of the study did provide distinct evidence of prolonged steroid-related side effects.

Other Measures

There were some other areas of effect to note during this study. For example, there was an increase in thrombocytes in current steroid abusers compared to ex-abusers. Thrombocytes are cells involved in blood clotting. Together with increased hematocrit and possibly blood pressure, this could increase the likelihood of serious adverse cardiovascular events such as blood clot or stroke. While still relatively rare, we have seen occasional reports of such in otherwise healthy anabolic steroid users. With regard to other common blood markers, there were no significant differences between groups in serum electrolytes (sodium, potassium, magnesium, calcium), iron, urea, creatinine, uric acid, glucose or HBA1. Lastly, while the researchers did not chart common cosmetic issues, they did report a high prevalence of gynecomastia in both groups (approximately two-thirds of subjects had or are currently dealing with it). Gynecomastia can be a permanent side effect of anabolic steroid misuse that requires surgery for correction. There are no surprises here.


In the context of this study, most of the short-term negative health effects of AAS misuse appeared to be reversible. In particular, former steroid users did not have the same unfavorable changes in red or white blood cell counts, serum cholesterol levels or liver enzyme values noted in current anabolic steroid users. The immediate effects of AAS on cardiovascular and liver health markers, which we know can be markedly negative, appear to go away after the drugs have been discontinued. These results do lend support for the acute safety of these drugs. They also mirror what we’ve seen in many short-term administration studies, which we touched on earlier in this piece. In this case, we are simply looking more broadly (and in a real-world context) at populations of users and former users for these same changes.

The reversibility of changes to basic health markers, of course, does not necessarily discount that there were changes in the first place. Disturbed health markers, even in the short term, could reflect underlying damage to our health. There is still much question as to whether a substantial period of AAS misuse could lead to a greater incidence of disease or death years later. For example, elevated cholesterol and LDL/HDL ratio are associated with heart disease-promoting changes in the cardiovascular system. Logically speaking, one might still be contributing to atherosclerosis (hardening of the arteries) during non-prescribed AAS administration, even if these health markers return to normal after. This is an area of medicine that needs much greater examination, of course. As mentioned in the opening of this article, such studies are lacking.

In the area of hormonal health, there does appear to be a valid reason for concern if you are contemplating the use of anabolic steroids. In the men of this study, a history of AAS misuse was associated with insufficient testosterone levels long after stopping. Low testosterone may cause immediate issues such as energy loss, impaired mental focus, reduced libido, and loss of strength and muscle mass. In the long term, however, more serious issues such as heart disease, diabetes and cancer have been linked to male hormone deficiency. It is conceivable that a “minor” problem with a low or even low-end-of-normal testosterone level after steroid use could foster considerable health issues later in life if not corrected. “Low T” is certainly a growing concern for aging men in clinical medicine. Therefore, one should consider both the positive and negative findings of this study before placing any weight on the results, one way or the other. As always, be safe.

William Llewellyn is widely regarded as one of the world’s foremost authorities on the use of performance-enhancing substances. He is the author of the bestselling anabolic steroid reference guide ANABOLICS and CEO of Molecular Nutrition. William is an accomplished researcher/developer in the field of anabolic substances, and is also a longtime advocate for harm reduction and legislative change. He built the website, an extensive online database of information on anabolic steroids and other performance-enhancing drugs.


Urhausen A, Torsten A, Wilfried K. Reversibility of the effects on blood cells, lipids, liver function and hormones in former anabolic-androgenic steroid abusers. J Steroid Biochem Mol Biol 2003;Feb;84(2-3):369-75.











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