Protein, amino acid metabolism and therapy: Edited by Erich RothGrowth hormone, arginine and exerciseKanaley, Jill AAuthor Information Department of Exercise Science, Syracuse University, Syracuse, New York, USA Correspondence to Jill A. Kanaley, PhD, 820 Comstock Ave, Rm 201, Syracuse, NY 13244, USA Tel: +1 315 443-9698; fax: +1 315 443-7375; e-mail: email@example.com Current Opinion in Clinical Nutrition and Metabolic Care: January 2008 - Volume 11 - Issue 1 - p 50-54 doi: 10.1097/MCO.0b013e3282f2b0ad Buy Metrics Abstract Purpose of review To describe the effect of an acute bout of exercise on growth hormone responses and to discuss the effect of L-arginine supplementation on growth hormone responses. Recent findings Recent studies have shown that resting growth hormone responses increase with oral ingestion of L-arginine and the dose range is 5–9 g of arginine. Within this range there is a dose-dependent increase and higher doses are not well tolerated. Most studies using oral arginine have shown that arginine alone increases the resting growth hormone levels at least 100%, while exercise can increase growth hormone levels by 300–500%. The combination of oral arginine plus exercise attenuates the growth hormone response, however, and only increases growth hormone levels by around 200% compared to resting levels. Summary Exercise is a very potent stimulator of growth hormone release and there is considerable research documenting the dramatic growth hormone rise. At rest oral L-arginine ingestion will enhance the growth hormone response and the combination of arginine plus exercise increases growth hormone, but this increase may be less than seen with exercise alone. This diminished response is seen in both in both younger and older individuals. © 2008 Lippincott Williams & Wilkins, Inc.