Stanozolol (also known as winstrol) is a 17-alpha-alkylated derivative of dihydrotestosterone (DHT) with low androgenic qualities yet highly anabolic. It was first developed in 1962 by American global pharmaceutical company Sterling-Winthrop Laboratories.

Stanozolol is a steroid anabolic. Penetrating into the cell nucleus, activates the genetic apparatus of the cell, which leads to an increase in DNA synthesis, RNA and structural proteins, activation of enzymes of the tissue respiration chain and increased tissue respiration, oxidative phosphorylation, ATP synthesis and accumulation of macroergs inside the cell. Stimulates anabolic and suppresses catabolic processes caused by glucocorticoids. It leads to an increase in muscle mass, reduction of fat deposits, improves tissue trophism, promotes calcium deposition in bones, retains nitrogen, phosphorus, sulfur, potassium, sodium and water in the body. Hematopoietic action is associated with an increase in the synthesis of erythropoietin.