Abstract Background/Aims: Recombinant human growth hormone (rhGH) as opposed to cadaver pituitary GH is misused for physical improvement. Six days' rhGH administration, in abstinent anabolic-androgenic steroid dependents, was compared with controls. Method: Male subjects (n = 48) were randomly divided into two groups: (1): control group (C), n = 24, mean ± SD, age 32 ± 11 years, height 1.8 ± 0.06 m; (2): rhGH-using group (0.058 IU·kg-1·day-1) (GH), n = 24, mean ± SD, age 32 ± 9 years, height 1.8 ± 0.07 m. Physiological measurements included anthropometry, strength, power and peak oxygen uptake (VO2 peak). Biochemical measurements included haemoglobin, packed cell volume, glucose, sodium, potassium, urea, creatinine, total protein, albumin, thyroid function, testosterone, prolactin, cortisol, GH and insulin-like growth factor-I (IGF-I). Results: Strength, peak power output and IGF-I significantly increased and total protein, albumin and free tetra-iodothyronine significantly decreased compared to controls (p andlt; 0.05) and within the GH group (p andlt; 0.017). Fat-free mass index and VO2 peak significantly increased, while body fat and thyroid-stimulating hormone significantly decreased within the GH group (p andlt; 0.017). Conclusions: Short-term rhGH increased strength and power. Of therapeutic value is the possibility that muscle bulk and strength could be increased in patients with muscle-wasting conditions.