Winstrol (stanozolol) is a synthetic anabolic steroid that increases the body’s ability to retain nitrogen, build lean muscle, and reduce fat, while simultaneously causing significant side effects to the liver, cholesterol, and hormonal system. It was originally developed for medical use and is derived from dihydrotestosterone, a naturally occurring male sex hormone. Here’s what it actually does inside the body and why it carries real risks.
How Winstrol Works in the Body
Winstrol’s core mechanism involves two things: activating androgen receptors in muscle tissue and suppressing a protein called sex hormone-binding globulin (SHBG). SHBG acts like a sponge for testosterone in your blood, binding to it and making it inactive. Stanozolol drives SHBG levels down to roughly 52% of their starting value, which means more free testosterone is available to act on tissues throughout the body.
The other major effect is nitrogen retention. Nitrogen is a building block of amino acids, and amino acids are what your muscles are made of. When your body retains more nitrogen than it loses, it’s in an anabolic state, meaning it’s building tissue faster than it breaks it down. In animal studies, oral stanozolol nearly doubled nitrogen retention (from about 29% to 50%), while the injectable form pushed it even higher, from roughly 27% to 67%. This is the primary reason people use it for physique or performance goals.
Effects on Muscle and Body Composition
Winstrol is known in bodybuilding circles as a “cutting” steroid. Unlike some anabolic steroids that cause noticeable water retention, stanozolol tends to produce a leaner, harder-looking physique. Research on strength-training athletes using anabolic steroids showed significant increases in lean mass, particularly in the arms compared to the trunk and legs. The percentage of fat in the legs also decreased during use and stayed lower even after the drugs were stopped.
Part of this effect may relate to how stanozolol interacts with an enzyme involved in cortisol activation (11-beta-HSD-1). By inhibiting this enzyme, stanozolol may counteract some of the fat-storing and muscle-wasting effects of cortisol. This is one reason users report a “drier” and more defined appearance compared to other steroids.
Its One Approved Medical Use
Stanozolol was FDA-approved for treating hereditary angioedema, a genetic condition that causes sudden, severe episodes of swelling in the face, throat, limbs, and intestinal wall. It reduced the frequency and severity of these attacks. However, the drug has since been discontinued from the U.S. market. Its medical use was always narrow, and the availability of safer alternatives made it largely obsolete in clinical settings.
Liver Toxicity
Winstrol belongs to a class called 17-alpha-alkylated steroids. This chemical modification allows it to survive passing through the liver when taken orally, but that survival comes at a cost. The liver has to process this resistant compound, and the result is a specific type of damage called cholestasis, where bile flow from the liver becomes impaired.
What makes this tricky is that standard liver blood tests can appear relatively normal even when significant damage is occurring. Cholestasis caused by stanozolol doesn’t always elevate the typical liver enzymes doctors check for. The damage is to the bile transport system rather than to liver cells themselves. In severe cases, this can progress to peliosis hepatis (blood-filled cysts in the liver) or, rarely, liver tumors. These risks increase with higher doses and longer use, but they exist at any dose because the drug’s chemical structure is inherently hard on the liver.
Cholesterol and Heart Risk
Winstrol’s impact on cholesterol is among the most dramatic of any anabolic steroid. A study published in JAMA gave male weight lifters 6 mg per day of oral stanozolol for six weeks and measured the results. HDL cholesterol (the protective kind) dropped by 33%. The HDL2 subfraction, considered the most heart-protective component, plummeted 71%. Apolipoprotein A-I, a key protein in HDL particles, fell by 40%.
On the other side of the equation, LDL cholesterol (the harmful kind) rose by 29%. The drug also more than doubled the activity of hepatic triglyceride lipase, a liver enzyme that breaks down HDL particles. This combination of suppressed HDL and elevated LDL creates a lipid profile that significantly increases cardiovascular risk, even in young, otherwise healthy users. These changes happen fast, within weeks of starting the drug, and are far more severe than what testosterone alone produces.
Hormonal Suppression and Recovery
Like all anabolic steroids, Winstrol suppresses your body’s natural testosterone production. When you introduce synthetic androgens, the brain’s signaling system (the hypothalamic-pituitary axis) detects the excess and dials down its own output of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), the hormones that tell the testes to produce testosterone.
The degree and duration of suppression depend heavily on dose and how long you use it. In one study, nine healthy men who took stanozolol at 10 mg per day for just two weeks saw their testosterone, LH, and FSH all drop, but all three recovered to baseline within two weeks of stopping. Longer and heavier use tells a different story. Power athletes who used stanozolol alongside other steroids for 26 weeks needed 12 to 16 weeks to recover, and in one group, testosterone levels were still about 11 nmol/L lower than baseline after 12 weeks. General findings across steroid recovery research suggest testosterone typically approaches full recovery within three to six months, though complete restoration isn’t guaranteed in every case.
The “Dry Joints” Problem
A common complaint among Winstrol users is joint pain, often described as “dry joints.” The explanation isn’t as simple as the drug drying out your joints. Interestingly, lab research shows stanozolol actually stimulates collagen synthesis in a dose-dependent manner, doubling the production of certain collagen types. It does this by upregulating a growth factor called TGF-beta1.
So why do joints hurt? The answer likely involves the lack of water retention. Steroids that cause more water retention tend to create a cushioning effect around joints. Because stanozolol doesn’t do this, and because it may alter the type or quality of connective tissue being produced, users often experience increased joint stiffness and discomfort, especially during heavy training. This is a practical concern for athletes, since joint injuries under heavy loads can be severe.
Detection in Drug Testing
Stanozolol is banned by the World Anti-Doping Agency and appears on every major sports organization’s prohibited list. After a single dose, its primary metabolite (3′-hydroxystanozolol) is detectable in urine for three to four days. With repeated use at performance-enhancing doses, the detection window extends considerably longer. Modern testing methods can identify stanozolol metabolites at concentrations as low as 2 nanograms per milliliter. This is the steroid that famously ended Ben Johnson’s 1988 Olympic gold medal, and testing sensitivity has only improved since then.
Oral vs. Injectable Forms
Winstrol comes in two forms: oral tablets and a water-based injectable suspension. Both carry the same 17-alpha-alkylated structure, meaning the injectable version is still processed by the liver and still carries hepatotoxicity risk, unlike most other injectable steroids. The elimination half-life is approximately 24 hours for both forms.
The injectable form does appear to be more potent on a milligram-for-milligram basis. Nitrogen retention studies in animals showed the injectable version increased retention to 67% compared to 50% for oral dosing. This difference is significant and explains why some users prefer injections despite the inconvenience. However, both routes deliver the same spectrum of side effects: liver stress, cholesterol disruption, hormonal suppression, and joint discomfort.