Stanozolol has a reputation as a "soft" steroid that does not retain water or cause gynecomastia. This reputation is partly deserved, but it distracts from the risks, which are more pronounced with stanozolol than with many other androgens. The editors have collected in one place all the main side effects of the drug, grouping them by organ systems and by the strength of the evidence.
Where the side effects come from
The adverse effect profile of any anabolic steroid is determined by three things: that it is an androgen; its specific chemical structure; and dose and duration of use. Stanozolol in this sense "inherits" the general risks of the class, to which are added the specific consequences of 17α-methylation and hepatic metabolism.
Since the drug is not aromatized, it has practically no estrogenic side effects: gynecomastia caused by stanozolol itself and pronounced fluid retention are not characteristic. This is what formed the idea of its "purity". However, the absence of some risks does not compensate for the strengthening of others.
It is important to distinguish between medical doses used, for example, to prevent attacks of hereditary angioedema, and doses used in a non-medical context. Observations in patients with angioedema (Sloane et al., 2007) show that even with long-term treatment at low doses, changes in liver enzymes, lipids and menstrual disturbances occur in women. In sports, doses and combinations with other drugs are usually much higher.
Another factor is quality. A large part of the stanozolol on the illegal market is made by hand, and the actual composition of the drug may differ from the declared one. This adds unpredictability to any risk assessment.
Liver and metabolism
Hepatic complications are the best known specific risk of stanozolol as a 17α-alkylated steroid. An increase in the activity of transaminases (ALT, AST) and gamma-glutamyltransferase is most often observed. It should be remembered that in people who train intensively, ALT and AST can rise from the muscles, so they should be evaluated together with bilirubin and GGT.
A more serious complication is cholestatic jaundice: impaired bile flow with yellowing of the skin, itching, dark urine. Such cases during stanozolol are described in the literature, sometimes with a severe course and long recovery. Rare but potentially fatal complications of the class are peliosis hepatis and liver tumors, particularly adenomas.
Metabolic effects are associated with hepatic influence on protein synthesis. A sharp decrease in SHBG changes the balance of free hormones, and changes in the synthesis of apolipoproteins and the activity of liver lipase lead to pronounced dyslipidemia. It is discussed in detail in the next chapter.
An effect on carbohydrate metabolism is also possible: a decrease in insulin sensitivity has been described for anabolic steroids in general, although data specifically for stanozolol are limited. People with impaired glucose tolerance should consider this aspect.
Heart, vessels and blood
The most documented cardiovascular effect of stanozolol is a decrease in HDL cholesterol. In a randomized comparison by Thompson et al. (1989), stanozolol at a dose of 6 mg/day lowered HDL by about a third and increased LDL, whereas testosterone enanthate at a dose of 200 mg/week changed HDL much less. This study itself is often cited as evidence of the particular "lipid toxicity" of oral steroids.
Anabolic steroids are generally associated with increased blood pressure, left ventricular hypertrophy, impaired diastolic function, and accelerated coronary atherosclerosis. These data, summarized in a statement by the Endocrine Society (Pope et al., 2014), refer mostly to long-term users who have combined different drugs.
Androgens stimulate the formation of erythrocytes, which increases hematocrit and blood viscosity. Stanozolol, in addition, affects the coagulation system and fibrinolysis. The cumulative effect on the risk of thrombosis in humans has not been clearly assessed, but there are descriptions of heart attacks and strokes in young AAS users.
Read more about lipids, blood pressure and hematocrit during stanozolol in a separate editorial article dedicated to the cardiovascular system.
| System | Main risks | Level of evidence |
|---|---|---|
| Liver | Increased enzymes, cholestasis, peliosis, adenomas | Case reports and reviews of 17α-alkylated steroids |
| Lipids | Pronounced decrease in HDL, increase in LDL | Randomized studies |
| Heart and vessels | Hypertension, myocardial hypertrophy, atherosclerosis | Observational studies of AAS users |
| Hormones | LH/FSH suppression, testosterone reduction, infertility | Evidence for the AAS class |
| Skin, hair | Acne, androgenetic alopecia | Clinical observations |
| Women | Virilization, cycle disruption | Clinical data, in particular in the treatment of angioedema |
Hormones, skin, musculoskeletal system, psyche
Like any androgen, stanozolol inhibits the hypothalamus–pituitary–gonadal axis. The levels of luteinizing and follicle-stimulating hormones decrease, own testosterone falls, and spermatogenesis is inhibited. After withdrawal, recovery can take months, and some people develop persistent hypogonadism.
Due to the fact that stanozolol is not aromatized, during its isolated use, estradiol can decrease along with its own testosterone. For men, this means the risk of decreased libido, mood swings and, with prolonged deficiency, negative effects on bones.
Androgenic effects on the skin include acne and accelerated baldness in genetically predisposed individuals. Because stanozolol is a DHT derivative, its effect on hair follicles is often rated as significant, although there are few comparative studies.
Regarding tendons and joints: There are reports of tendon tears in anabolic steroid users, and animal data suggest changes in collagen structure. However, the causal relationship with stanozolol in humans has not been proven. Psychiatric effects—irritability, aggression, mood swings, post-withdrawal depression—are described for class AAS in general.
Who is at high risk
Some people are more vulnerable to the side effects of stanozolol than others. For them, even short-term use can have disproportionately serious consequences. The list below is not exhaustive, but covers the main categories.
- people with liver diseases, including non-alcoholic fatty liver disease and chronic hepatitis;
- people with dyslipidemia, arterial hypertension or cardiovascular diseases in the family history;
- adolescents, in whom androgens can prematurely close bone growth zones;
- women, especially pregnant women and those planning to become pregnant, because of the risk of virilization of the fetus and the woman herself;
- people taking anticoagulants: anabolic steroids, particularly stanozolol, may increase the effects of warfarin.
Interaction with anticoagulants deserves special attention. Enhancement of the effect of warfarin during 17α-alkylated androgens is known from clinical practice and required dose correction and more frequent monitoring of INR in patients. The independent combination of such drugs is dangerous for bleeding.
We will separately mention people prone to depression or addictions. For some users of AAS, the formation of dependence is described with continued use despite the harm, and the period after withdrawal is accompanied by a decrease in mood due to hormonal deficiency.
Finally, the risks increase for those who combine stanozolol with alcohol, other hepatotoxic substances, or other anabolic steroids. The total load on the liver and lipid metabolism in such cases is difficult to predict.
Editorial conclusions
Stanozolol does not cause estrogenic side effects, but has a pronounced negative effect on the liver and lipid profile - in studies stronger than that of injectable testosterone.
Like all androgens, it suppresses its own hormonal system, affects the skin, blood and psyche. For women, the main risk is virilization, some of which are irreversible.
The perception of stanozolol as a "safe" or "mild" steroid is not supported by the available data. Risks increase with dose, duration, and combination with other substances.
For a more detailed understanding of individual aspects, we advise you to read our articles on the effects of stanozolol on the cardiovascular system, on the tests that should be monitored, and on the risks of virilization in women.
References
- Pope HG Jr, Wood RI, Rogol A, et al. Adverse health consequences of performance-enhancing drugs: an Endocrine Society scientific statement. Endocr Rev. 2014;35(3):341â375.
- Thompson PD, Cullinane EM, Sady SP, et al. Contrasting effects of testosterone and stanozolol on serum lipoprotein levels. JAMA. 1989;261(8):1165â1168.
- Sloane DE, Lee CW, Sheffer AL. Hereditary angioedema: safety of long-term stanozolol therapy. J Allergy Clin Immunol. 2007;120(3):654â658.
- Solimini R, Rotolo MC, Mastrobattista L, et al. Hepatotoxicity associated with illicit use of anabolic androgenic steroids in doping. Eur Rev Med Pharmacol Sci. 2017;21(1 Suppl):7â16.
- Hartgens F, Kuipers H. Effects of androgenic-anabolic steroids in athletes. Sports Med. 2004;34(8):513â554.
- Rahnema CD, Lipshultz LI, Crosnoe LE, et al. Anabolic steroid-induced hypogonadism: diagnosis and treatment. Fertil Steril. 2014;101(5):1271â1279.
- Kicman AT. Pharmacology of anabolic steroids. Br J Pharmacol. 2008;154(3):502â521.
