The purpose of this study was to determine the effects of 8 weeks of norsteroid supplementation on body composition and athletic performance in previously weight-trained males. Subjects were weight and percent body fat matched and randomly assigned to receive either 100 mg of 19-nor-4-androstene-3,17-dione (N-dione) and 56 mg of 19-nor-4-androstene-3,17-diol (N-diol; 156 mg total norsteroid per day), or a placebo (a multivitamin). Each subject participated in resistance training 4 days/week for the duration of the study. Body composition was assessed via dual-energy X-ray absorptiometry. Circumference measures were taken of a relaxed and flexed arm (maximum circumference of the arm), waist (level of umbilicus), and thigh (15 cm proximal to the patella). Strength was determined with a one-repetition maximum bench press, while force and power were determined with a dumbbell bench press (60% body weight) on a Stratec Galileo force platform. Profile of mood states scores were evaluated for vigor and fatigue. There were no significant changes in any of the parameters measured. In conclusion, low-dose supplementation with N-dione and N-diol does not appear to alter body composition, exercise performance, or mood states.