Do arginine, ornithine, and citrulline cause diarrhea?
Using these criteria, the literature was searched for all trials in which oral arginine, ornithine, and citrulline had been given to healthy volunteers or patients (Table 1). The writer was struck both by the wide indications for these compounds and by the lack of consensus on dosage regimes (Table 1). Reporting of adverse effects was often inconsistent or nonexistent and, even where placebo and treatment had been compared, the incidence of gastrointestinal side effects varied greatly (Table 1). In some studies, authors commented on tolerance to the oral supplement; several studies reported no side effects even when large doses were administered. Side effects did not appear to be related to the concentration of plasma L-arginine that was achieved and would provide the substrate for systemic NO synthesis.
