Oxymetholone (also known as Anadrol or Anapolon) is an orally effective C17-alpha-alkylated modification of dihydrotestosterone that is considered by many to be one of the most powerful steroids commercially available. Released in the United States as a prescription drug during the early 1960s under the famous brand name Anadrol-50, oxymetholone is a very potent steroid that was developed for the treatment of osteoporosis and anemia, as well as to stimulate muscle gain in malnourished and debilitated patients. The hydroxymethylene group at the carbon C2 position is a unique structural feature of oxymetholone that greatly enhances anabolic effects and biological activity, resulting in significantly higher anabolic activity than testosterone. Oxymetholone dramatically provokes both rapid bulk muscle mass gains and a significant increase in strength and power performance. In addition, it is often known for promoting water retention, which can lead to high blood pressure while on cycle. As a result of its ability to increase the level of hemoglobin and blood volume in the body, oxymetholone may cause an extremely strong muscle pump effect, which consequently may complicate training because some users experience such an extreme pump that the muscles may become sore after the first heavy set. 

As a derivative of dihydrotestosterone, oxymetholone does not have a chemical structure that aromatizes. However, oxymetholone itself has pronounced estrogenic properties. Because of this peculiarity, only antiestrogens (estrogen receptor blockers/SERMs) are able to combat the potential estrogenic side effects, but not aromatase inhibitors because aromatase is not involved in the process. It has been suggested that the estrogenic activity of oxymetholone may be related to a progestogenic effect similar to that of nandrolones; however, while the side effects may appear similar, medical studies have shown that oxymetholone does not possess any progestogenic activity. 

WARNING: Due to its C17-alpha-alkylation, oxymetholone may exert high stress on the liver. Therefore, healthy lifestyle choices and the use of supplements to promote liver health are advisable. For this reason, the recommended oxymetholone cycle duration should be no more than 6 weeks.