Bodybuilders primarily use anabolic-androgenic steroids (AAS), synthetic derivatives of testosterone designed to amplify muscle growth while attempting to minimize androgenic side effects like body hair growth and voice deepening. The most commonly encountered compounds include testosterone itself (in injectable ester forms like enanthate and cypionate), nandrolone (Deca-Durabolin), stanozolol (Winstrol), oxandrolone (Anavar), methandienone (Dianabol), boldenone (Equipoise), and trenbolone. These drugs were first developed after testosterone was isolated in the 1930s, and they spread rapidly through elite athletics and bodybuilding from the 1950s onward. The risks they carry are serious, affecting the heart, liver, kidneys, hormonal system, and brain in ways that can outlast the muscle gains.
How These Drugs Build Muscle
All anabolic-androgenic steroids work through the same core mechanism: they enter cells and bind to the androgen receptor, a protein expressed in skeletal muscle, the liver, the prostate, and the central nervous system.1PubMed. Structural characteristics of anabolic androgenic steroids contributing to binding to the androgen receptor and to their anabolic and androgenic activities Once bound, the receptor complex moves into the cell nucleus and switches on genes involved in protein synthesis, nitrogen retention, and recovery from training. Inside cells, AAS can also be converted into different metabolites that exert their own effects.2PubMed Central. Anabolic-androgenic steroids: How do they work and what are the risks? The result is faster and greater muscle growth than training alone can produce, along with reduced recovery time between workouts.
Different steroids are chemically modified to shift the balance between anabolic (muscle-building) and androgenic (masculinizing) effects, to change how long they stay active in the body, or to survive being swallowed. Oral steroids like stanozolol and methandienone are altered at a specific position on the molecule so they can pass through the liver without being immediately broken down. That modification is precisely what makes them more toxic to the liver than injectable compounds.3PubMed. Anabolic Steroid Effect on the Liver
Common Compounds and Why Bodybuilders Choose Them
Testosterone in its various injectable forms is the foundation of nearly every steroid regimen. It is the hormone the body already produces, which makes it the baseline that other compounds are stacked on top of. Bodybuilders typically use esterified versions (testosterone enanthate, cypionate, or propionate) that release slowly from the injection site, allowing weekly or biweekly dosing. Doses used for bodybuilding far exceed what doctors prescribe for hormone replacement, sometimes by a factor of five to ten.
Nandrolone decanoate (Deca-Durabolin) is popular for off-season “bulking” because it promotes significant muscle mass and is considered moderately androgenic. Boldenone undecylenate (Equipoise), originally a veterinary product, is favored for lean gains and appetite stimulation. Methandienone (Dianabol), one of the earliest oral steroids, remains widespread for quick strength and size gains at the start of a cycle, despite its pronounced liver toxicity and water retention.
Stanozolol (Winstrol) and oxandrolone (Anavar) are oral compounds often used in “cutting” phases before competitions, since they tend to build lean tissue without heavy water retention. Stanozolol is also one of the best-studied oral steroids for its dramatic effects on cholesterol, which will come up shortly.
Trenbolone stands out as the compound with perhaps the most potent reputation and the most troubling safety profile. An international survey of over 1,100 male AAS users found that those who used trenbolone reported significantly more mood instability, irritability, depressive symptoms, cardiovascular problems, and liver-related effects compared to steroid users who did not use trenbolone.4PubMed Central. The Trenbolo(g)ne Sandwich: An International Study Comparing Health Harms Among Men Who Use Anabolic-Androgenic Steroids With and Without Trenbolone That finding is striking because the comparison group was not non-users but other steroid users, suggesting trenbolone adds a layer of harm on top of what AAS already carry.
Cycling, Blasting, and Cruising
Bodybuilders do not simply take a fixed dose indefinitely (though a small minority do). A study of gym-going AAS users classified their patterns into three groups: about half cycled on and off steroids with drug-free breaks in between, roughly 43% alternated between high-dose “blast” phases and lower-dose “cruise” phases without ever fully stopping, and the remaining fraction maintained a steady continuous dose.5PubMed Central. Anabolic Androgenic Steroid Use Patterns and Steroid Use Disorders in a Sample of Male Gym Visitors The blast-and-cruise approach has become increasingly common among more dedicated users because it avoids the hormonal crash of going fully off cycle, though it also means the body never gets a genuine recovery period.
“Stacking” is the practice of combining multiple steroids in a single cycle, often mixing an injectable testosterone base with one or two additional compounds chosen for specific goals. Advanced users frequently add non-steroidal drugs to their stacks as well, including growth hormone and insulin-like growth factor (IGF-I), which are used to amplify the anabolic effects of the steroids.6PubMed Central. Use of Growth Hormone, IGF-I, and Insulin for Anabolic Purpose: Pharmacological Basis, Methods of Detection, and Adverse Effects Insulin itself is another addition at the elite level, and it carries its own life-threatening risk of hypoglycemia. The trend in competitive bodybuilding has been toward ever-more-complex polysubstance protocols, which makes isolating the harm from any single drug extremely difficult.
What Steroids Do to the Heart
Cardiovascular damage is the single largest health concern with AAS use, and the evidence here is extensive. A prospective study (the HAARLEM study) followed steroid-using bodybuilders through a full cycle and recovery period. After a median cycle of about 16 weeks, the heart’s pumping efficiency dropped measurably, and the left ventricle gained an average of about 28 grams of mass, a thickening that correlated with higher weekly steroid doses. The good news: after roughly eight months of recovery, these changes reversed to baseline in most participants.7PubMed Central. Anabolic Androgenic Steroids Induce Reversible Left Ventricular Hypertrophy and Cardiac Dysfunction: Echocardiography Results of the HAARLEM Study The bad news: many users never take an eight-month break, and repeated cycles may cause cumulative damage that eventually becomes irreversible.
Steroids also wreak havoc on cholesterol. They stimulate an enzyme in the liver that breaks down HDL (“good”) cholesterol while raising LDL (“bad”) cholesterol.8International Journal of Sports and Exercise Medicine. Extremely Low HDL Cholesterol and Increased LDL Cholesterol Induced by the use of Anabolic Steroids in a Body Builder: A Case Study The oral steroid stanozolol is particularly aggressive in this regard: in a controlled study, HDL cholesterol dropped about 40% within just seven days of administration, driven by a rapid rise in hepatic triglyceride lipase activity that began within the first day.9PubMed. The dyslipoproteinemia of anabolic steroid therapy: increase in hepatic triglyceride lipase precedes the decrease in high density lipoprotein2 cholesterol Over years, chronically distorted cholesterol panels accelerate atherosclerosis, raising the risk of heart attack and stroke.
A large epidemiological study tracking over 20,000 male competitive bodybuilders over 16 years found an overall death rate of roughly 64 per 100,000 athlete-years, with sudden cardiac death accounting for 38% of all recorded deaths at an average age of just 42.10European Heart Journal. Mortality in male bodybuilding athletes While the study could not confirm individual steroid use, widespread AAS use in competitive bodybuilding is well documented, and the rate of sudden cardiac death in these athletes far exceeds what you would expect in a general population of men that age.
Liver and Kidney Damage
Oral steroids pose the most direct threat to the liver. The chemical modification that lets them survive first-pass metabolism also causes a specific pattern of liver injury, including cholestasis (a blockage of bile flow), peliosis hepatis (blood-filled cysts in the liver), and, in rare cases, benign or malignant liver tumors.11PubMed Central. Anabolic androgenic steroid-induced liver injury: An update Injectable testosterone esters are less hepatotoxic because they bypass the digestive tract, but they are not entirely benign at supraphysiologic doses.
Kidney damage from AAS receives less attention but deserves it. Researchers identified a pattern of focal segmental glomerulosclerosis (FSGS), a form of kidney scarring, in a group of ten bodybuilders after long-term steroid abuse. They proposed that the damage results from a combination of the kidneys adapting to increased lean body mass and potential direct toxic effects of the steroids themselves. Because bodybuilders carry so much muscle, their baseline creatinine levels (a standard marker of kidney function) are already elevated, which means early kidney disease can fly under the radar.12PubMed Central. Development of focal segmental glomerulosclerosis after anabolic steroid abuse In at least one documented case, kidney function improved after the user stopped all performance-enhancing drugs and began treatment, suggesting some reversibility if caught early.13Polish Annals of Medicine. Focal segmental glomerulosclerosis as a rare side effect of combined anabolic-androgenic steroid use, high-protein diet and high-intensity anaerobic training
Hormonal Shutdown and Fertility
When you flood your body with external testosterone or its derivatives, the brain’s signaling loop that controls natural testosterone production shuts down. The pituitary gland stops releasing the hormones (LH and FSH) that tell the testes to work. The testes shrink, sperm production plummets, and natural testosterone levels crater. Men who stop using steroids often face a period of very low testosterone that brings fatigue, depression, erectile dysfunction, and in some cases suicidal thoughts.14PubMed Central. Survey of endocrinologists managing recovery from anabolic androgenic steroid induced hypogonadism Studies of power athletes show that this suppressed state can persist for weeks after the last dose.15PubMed. Testicular responsiveness to human chorionic gonadotrophin during transient hypogonadotrophic hypogonadism induced by androgenic/anabolic steroids in power athletes
Gynecomastia, the development of breast tissue in men, is another common hormonal side effect. It happens because excess testosterone can be converted into estrogen by the aromatase enzyme. When estrogen levels rise disproportionately, breast glandular tissue grows. The connection between aromatase activity and gynecomastia is well established across multiple clinical settings.16PubMed. Aromatase and gynecomastia Bodybuilders often try to manage this with anti-estrogen drugs, but these carry their own side effects and do not always prevent the problem.
Recovery After a Cycle
Post-cycle therapy (PCT) is the protocol bodybuilders use to try to restart natural hormone production after a steroid cycle. A recent comparative study of recreational bodybuilders tested three approaches: no treatment (just waiting), clomiphene citrate alone (a drug that stimulates the brain to release gonadotropins), and clomiphene plus human chorionic gonadotropin (hCG, which directly stimulates the testes). Both drug regimens sped up hormonal recovery compared to doing nothing, and hormone levels normalized across all groups by about six months. Sperm recovery told a different story: at 12 months, normal sperm parameters were found in about 88% of the combination group, 69% of the clomiphene-only group, and only 59% of those who received no treatment.17PubMed. Post-cycle therapy after short-term anabolic-androgenic steroid use: comparative outcomes in recreational bodybuilders
For men whose sperm production drops to zero and does not recover on its own, more aggressive hormonal treatment can sometimes restore fertility. One case report documented a man with steroid-induced azoospermia who achieved normal sperm counts after three months of treatment with hCG and human menopausal gonadotropin (hMG), and his partner conceived naturally seven months later.18PubMed. Successful treatment of anabolic steroid-induced azoospermia with human chorionic gonadotropin and human menopausal gonadotropin Recovery is possible, but it is not guaranteed, especially after prolonged or heavy use.
Psychological and Behavioral Effects
The “roid rage” stereotype oversimplifies something real but more nuanced. Aggression, irritability, and even manic episodes are associated with steroid use, and in rarer cases, psychosis and suicidal behavior have been reported.19PubMed. Behavioural manifestations of anabolic steroid use A systematic review of AAS-using athletes found that psychiatric symptoms are common, including mood disorders, eating disorders, and body image disturbances like muscle dysmorphia, a condition in which someone perceives themselves as small and weak despite being heavily muscled. Long-term use tends to produce depressive symptoms, while short-term high doses are more associated with hypomanic states. Withdrawal and discontinuation often bring their own wave of depression.20PubMed Central. Anabolic-androgenic steroid use and psychopathology in athletes. A systematic review
Dependence is a genuine clinical concern. AAS dependence is classified in the DSM-5, and network analysis among male weightlifters has shown that the symptom patterns involve intertwined physical and psychological challenges. People continue using partly because they fear the hormonal crash and muscle loss that follow cessation, creating a cycle that is difficult to break without addressing both the somatic and mental health components.21PubMed Central. Investigating anabolic-androgenic steroid dependence and muscle dysmorphia with network analysis among male weightlifters
Risks Specific to Women
While the bodybuilding steroid conversation centers on men, women who use AAS face a set of additional complications. Prolonged use or high doses are linked to voice deepening (which is often irreversible), clitoral enlargement, menstrual irregularities, and the same cardiovascular complications seen in men. Mood changes and psychiatric symptoms affect women as well.22PubMed Central. Impacts of Anabolic-androgenic steroid supplementation on female health and offspring: Mechanisms, side effects, and medical perspectives Women in competitive bodybuilding and figure sports typically use lower doses of milder compounds like oxandrolone or primobolan, but “milder” is relative. Even compounds considered low-androgenic can cause virilizing effects in women at doses needed for competitive physique development. Some changes, particularly to the voice and facial structure, do not fully reverse after stopping.
Tendon Ruptures
There is an underappreciated irony in steroid-assisted training: while muscles grow rapidly, tendons and connective tissue do not keep pace. A cross-sectional study comparing AAS users and non-users found that 22% of steroid users reported at least one tendon rupture in their lifetime, versus 6% of non-users. The risk was roughly nine times higher in the AAS group. Upper-body tendon ruptures were especially telling: they occurred exclusively in steroid users (17% of the AAS group, zero non-users), while lower-body rupture rates were not significantly different between groups.23PubMed Central. Ruptured Tendons in Anabolic-Androgenic Steroid Users: A Cross-Sectional Cohort Study The likely explanation is that steroid-enhanced muscles generate forces that exceed what the tendons can handle, particularly in the upper body where the absolute strength gains tend to be largest.
What Is Actually in the Vial
Because most AAS are obtained through black-market channels, product quality is a wild card that adds risk on top of the pharmacological dangers. A systematic review and meta-analysis of studies analyzing black-market steroids found that a substantial proportion are counterfeit or substandard, putting users in a position of “unpredictable uncertainty” about what they are actually injecting.24PubMed Central. Fake anabolic androgenic steroids on the black market – a systematic review and meta-analysis on qualitative and quantitative analytical results found within the literature Forensic analysis of 42 illegally distributed products found that more than a third did not contain the expected ingredient. Counterfeits of premium-priced compounds like trenbolone (sold as Parabolan) and metenolone (sold as Primobolan) were especially common, often containing cheaper substitutes like nandrolone or testosterone. In some cases, products contained no active steroid at all or contained unexpected substances like progesterone.25Journal of Forensic Sciences. Black Market in Anabolic Steroids—Analysis of Illegally Distributed Products
This means a bodybuilder who believes they are running a carefully planned stack of specific compounds may actually be taking something entirely different, at a different dose, with a different side-effect profile. Contamination with bacteria or particulate matter in unsterile manufacturing environments adds infection risk on top of pharmaceutical unpredictability. Some harm reduction organizations now advocate for users to send samples for anonymous testing, though access to such services remains limited.
How Anti-Doping Testing Works
Drug testing in competitive sports relies primarily on urine analysis. The standard approach uses gas chromatography-mass spectrometry to identify steroids and their metabolites, though distinguishing pharmaceutical testosterone from the body’s own production requires more sophisticated methods. One established technique compares the ratio of testosterone to epitestosterone in urine; another measures the carbon isotope ratio of urinary steroids, which differs between synthetic and naturally produced testosterone.26PubMed Central. Testosterone and doping control Newer liquid chromatography methods can detect metabolites of at least 21 different anabolic steroids at very low concentrations in urine.27PubMed. Urinary detection of conjugated and unconjugated anabolic steroids by dilute-and-shoot liquid chromatography-high resolution mass spectrometry
These advances have made it increasingly difficult to use AAS in tested sports without detection, though a cat-and-mouse game continues. Some users switch to compounds with shorter detection windows, micro-dose to stay below reporting thresholds, or use so-called “designer steroids” that have been chemically modified to evade the specific metabolites labs screen for. In untested bodybuilding federations, which make up the majority of competitive bodybuilding, none of this matters. The drugs are an open secret, and the physiques on stage would be physiologically impossible without them. That disconnect between tested and untested competition is something any newcomer to the sport should understand clearly before setting goals based on what they see on stage or social media.