Disclosed is a method of treatment or prevention of frailty in an elderly patient, particularly having an age of 60 or older. The method provides the concomitant parenteral administration of a combination of an anabolic steroid and a vitamin D compound. A preferred combination comprises nandrolone decanoate and cholecalciferol (Vitamin D 3 ). The invention, in a further preference, provides a booster therapy to support frail elderly that have undergone hospitalization or surgery to retain independence and regain their regular physical and mental activities.