Nandrolone phenylpropionate (NPP), or nandrolone phenpropionate, sold under the brand name Durabolin among others, is an androgen and anabolic steroid (AAS) medication which has been used primarily in the treatment of breast cancer and osteoporosis in women. NPP has been used mainly in the treatment of advanced breast cancer in women and as an adjunct therapy for the treatment of senile or postmenopausal osteoporosis in women.Historically, it has also had a variety of other uses. Because of its reduced androgenic effects, the drug has not generally been used in androgen replacement therapy for androgen deficiency in men and has instead been used for solely for anabolic indications.