Nandrolone Decanoate is a man-made steroid, similar to the naturally occurring steroid testosterone. Nandrolone Decanoate is used to promote weight gain following extensive surgery, chronic infection, or severe trauma, and in other cases that result in inadequate weight gain or maintenance. Nandrolone Decanoate is used to decrease muscle loss caused by treatment with corticosteroids and to reduce bone pain associated with osteoporosis. Decaject is also used to treat anemia associated with chronic (long-term) kidney failure.

The decanoate salt form of Nandrolone, an anabolic steroid analog of testosterone with androgenic, anabolic, and erythropoietin stimulating effects. Nandrolone enters the cell and binds to and activates specific nuclear androgen receptors in responsive tissue, including the prostate, seminal vesicles, scrotum, penis, larynx, hair follicles, muscle, and bone. The resulting activated hormone receptor complex trans locates into the nucleus and binds to androgen response elements (ARE) in the promoter region of targeted genes, where the complex promotes gene expression necessary for maintaining male sex characteristics. Mimicking the negative feedback mechanism of testosterone, Nandrolone Decanoate also suppresses the secretion of luteinizing hormone (LH). Furthermore, this agent also stimulates Erythropoietin production by enhancing the production of erythropoietic stimulating factors.