What is Stanozolol?

UPDATED: May 19, 2025

Background

Stanozolol, also known as Winstrol, is a synthetic steroid that is derived from dihydrotestosterone and has anabolic and androgenic properties. It first came on the market in 1962. Over time, the marketing and labeling of stanozolol has been altered due to FDA requirements and changes in the drug market.  It is currently classified as a Schedule III Controlled Substance.  

Use

Stanozolol can be administered orally or intramuscularly. Some of its therapeutic uses include the treatment of aplastic anemia and hereditary angioedema, although it is rarely used for these conditions because better treatment options exist. It has also been indicated as a treatment of various other medical conditions, such as vascular disorders, central precocious puberty, and growth failure.

Side Effects

Side effects of stanozolol include those commonly associated with anabolic androgenic steroids, including menstrual irregularities, acne, atrophy of the breasts in women, and for men, impotence, testicular atrophy, and prostatic hypertrophy . Risks of altered lipid and cholesterol leading to arteriosclerosis, heart attacks, strokes, liver damage, and psychiatric disturbances could occur in both sexes. 

Sport Rules

The drug was first banned in sport by the International Olympic Committee and the International Amateur Athletic Federation (IAAF) in 1974. Its notable mark on sport history came in 1988, when Canadian sprinter Ben Johnson tested positive for stanozolol at the Olympic Games and was stripped of his gold medal in the 100 meters. 

Stanozolol  is prohibited at all times under the World Anti-Doping Agency (WADA)  Prohibited List  in the category of Anabolic Agents.  

Urinary metabolites of stanozolol can be easily detected by methods such as gas chromatography-mass spectrometry (GC-MS) and liquid chromatography tandem mass spectrometry (LC-MS/MS) at very high sensitivity. In 2013, new long-term stanozolol metabolites were discovered and published, dramatically extending the detection window after drug use, leading to an extreme increase in the number of positive findings after retrospective analysis of stored athlete samples. These long-term metabolites now form an important basis for routine urine screening for stanozolol abuse in sport. Under the World Anti-Doping Code, athletes who test positive for stanozolol could potentially face a four-year sanction. 

Dietary Supplement Risk

Athletes are responsible for what they put in their body. Unfortunately, dietary supplements pose a risk to athletes and consumers because they can be mislabeled to incorrectly represent the ingredients contained therein. In the past, investigations of some nutritional supplements have revealed the presence of prohibited substances not listed on the labels, including anabolic steroids such as stanozolol.  

USADA’s Supplement Connect resource can help athletes make informed decisions in order to realize, recognize, and reduce their risks when it comes to taking dietary supplements. The use of any dietary supplement is at the athlete’s own risk.