Chronic respiratory insufficiency leads to protein-calorie malnutrition (PCM). PCM results in increased morbidity (e.g., infection), which in turn promotes further body wasting. The latter leads to respiratory muscle dysfunction and acute respiratory failure. Nutritional support alone is generally insufficient to counterbalance this hypoxemic and stress-related muscle catabolism. Recombinant human growth hormone (rhGH) can preserve or replenish nitrogen reserves, mostly contained in body muscle mass. It was hypothesized that rhGH, through its ability to improve muscle mass and function, could be a valuable therapeutic adjunct in both chronic and acute respiratory insufficiency. The results are controversial, and the beneficial effects of rhGH in patients with chronic and acute respiratory insufficiency, in terms of improvement of respiratory function, morbidity, and quality of life, remain to be shown. Well-designed studies, specifically targeting these end points as well as cost-effectiveness, are needed to better define the place of rhGH in the nutritional support of these patients.