L-Ornithine is a nonessential amino acid. The body uses ornithine to produce l-arginine as well as l-proline and polyamines. During this process, ornithine stimulates the release of growth hormones by the pituitary gland. Ornithine demonstrates putative anabolic and imunomodulatory activities. The functions of ornithine are closely tied to those of l-arginine.

At the time, there have been no recorded drug interactions with the usage of l-ornithine.

Ornithine is well tolerated by most people. When taken in the proper dosage, no side effects have been reported. However, if large amounts (above 10 grams daily) are used, nausea, abdominal cramps and diarrhea may be experienced.