Growth Hormone As the name implies, growth hormone (GH) promotes growth of many tissues. Growth hormone is a peptide hormone secreted from the anterior pituitary. In skeletal muscle, GH promotes a positive protein balance by increasing protein synthesis and possibly inhibiting protein breakdown. There has been interest in ways to acutely elevate GH to promote an anabolic environment and enhance adaptations to resistance training. Although infusion and in some cases oral ingestion of large doses of certain amino acids (e.g., arginine, lysine, and ornithine) can increase GH levels, the effect is quite variable and reduced in trained individuals. Resistance exercise is a potent stimulus that increases GH immediately after exercise. A few studies have shown that this GH response can be augmented by consuming a protein and carbohydrate supplement before and immediately after resistance exercise. However, few supplements beyond protein and carbohydrate based products have been tested in respect to boosting GH responses to exercise. In a report presented at the International Society of Sports Nutrition Conference and Expo, researchers examined alpha-glycerylphosphorylcholine, a precursor to the neurotransmitter acetylcholine. Trained subjects consumed either the alpha-glycerylphosphorylcholine or a placebo 90 min before performing an intense bout of squat exercises. Several blood samples were analyzed for GH during the 2 hours period after exercise. Similar to many other studies, GH was increased in response to resistance exercise peaking about 30 min into recovery. Peak levels were significantly higher during the alpha-glycerylphosphorylcholine trial (8.4 ng/mL) compared to placebo (5.0 ng/mL). this study provides some intriguing pilot data showing a GH potentiating effect of a single dose of alpha-glycerylphosphorylcholine in trained men.

Ziegenfuss T, Landis J, Hofheins J. Acute supplementation with alpha-glycerylphosphorylcholine augments growth hormone response to, and peak force production during, resistance exercise. Journal of the International Society of Sports Nutrition 2008, 5(Suppl 1):P15