Arginine and ornithine are amino acids that are generally used by weightlifters to help repair and strengthen muscle tissue after weight lifting. The popular muscle building supplement creatine is a product of arginine; a deficiency of either amino acid can unsurprisingly result in muscle weakness. In order to use arginine and ornithine to their fullest potential as muscle builders, it's important to know how much to take and when.
For a two-hour period following an intense workout, the body experiences increased testosterone and growth hormone production. In that two-hour period, supplemental arginine and ornithine dosages can help increase the production of protein synthesis and muscle growth.
The best way to utilize arginine and ornithine as growth hormone stimulants is to take a dose immediately following a period of strenuous exercise, and another dose at bedtime on an empty stomach. Additionally, nutritionist Dr. Michael Colgan recommends taking arginine and ornithine regularly for two months while engaged in a steady workout regimen, then stopping the dosages for two months, before starting the dosage cycle again.
Colgan delineates appropriate levels of arginine and ornithine dosages in "Optimum Sports Nutrition: Your Competitive Edge." According to Colgan, a week of strength training totaling between four and 10 hours, for a person weighing between 170 and 220 lbs., would require approximately 9 grams of a combined arginine/ornithine supplement. For a total strength training week of 11 to 17 hours, the dosage should be increased to 12 grams of arginine/ornithine. Last, for a strength-training week falling between 18 and 24 hours, the proper dosage would be 15 grams.
The pituitary gland supplies the growth hormone that facilitates the formation of tissue and bone matter, which are made from amino acids. Without enough ornithine, the pituitary gland couldn't produce the growth hormone necessary to repair the muscle tissue that's injured during exercise. While ornithine is twice as effective in this regard than arginine, the two amino acids are most effective in stimulating muscle tissue repair when working in tandem.
According to a study referenced by the U.S. National Library of Medicine, adult males who participated in a five-week strength-training program, and who were given 1-2 gram dosages of arginine and ornithine during that time, showed noticeably improved levels of total strength and lean body mass. The study also determined that arginine and ornithine helped suppress the tissue breakdown that accompanies chronic stress.