Rationale: Growth hormone (GH) replacement in GH deficient adults results in an improvement in metabolic status. GH might also decrease visceral adiposity in obese adults that are not GH deficient.

Objective: To determine the effects of supraphysiological GH therapy on the metabolic syndrome and visceral adiposity in men with low blood levels of IGF-1 and the durability of these effects after stopping GH therapy.

Design: A double blind, placebo controlled 6 month intervention trial followed by a blinded follow-up period of 6 months.

Subjects: Thirty non-diabetic middleaged men with central adiposity (BMI > 27 kg/m², waist circumference > 102 cm) participated.

Results: After 6 months of GH therapy we observed an increase in weight and lean body mass (2.5 + 0.6 kg, p < 0.05 compared to baseline and placebo) and 8.8% reduction in visceral adiposity. GH increased resting energy expenditure by 172.5 ± 41.6 kcal/24h after 6 months therapy. Fasting insulin, glucose and the QUICKI insulin resistance index increased during GH therapy. The effects of GH on fatness and visceral adiposity disappeared shortly after GH withdrawal, but weight remained increased over baseline and when compared to the placebo group (p < 0.05).

Conclusion: These data suggest that GH therapy is associated with small but statistically significant decreases in visceral adiposity and an increase in lean mass and body weight. In viscerally obese subjects supraphysiological GH administration is not an effective treatment, however further studies are needed to evaluate the effects of low-dose, physiological GH treatment.