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 DEACONATE AND CHOLECALCIFEROL (VITAMIN D3). 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.