Arginine, or L-arginine, is considered a semi-essential amino acid, because although it is normally synthesized in sufficient amounts by the body, supplementation is sometimes required (for example, due to inborn errors of urea synthesis, protein malnutrition, excess ammonia production, excessive lysine intake, burns, infection, peritoneal dialysis, rapid growth, or sepsis). A well-designed multicenter, randomized, controlled clinical trial found that ibuprofen-arginate (Spedifen) reduced pain faster after dental surgery compared to conventional ibuprofen alone. The study included 498 patients who were given ibuprofen-arginate, ibuprofen, or placebo after dental surgery. It was found that ibuprofen arginate relieved pain faster and adverse events with ibuprofen-arginate were similar to those seen with ibuprofen alone. Another similar trial concluded that patients treated with ibuprofen-arginate rated its overall effectiveness higher than those treated with ibuprofen alone. Adverse event profiles were similar across all treatment groups. Further research is needed in this area.