In addition to potentially reducing body fat and improving muscle mass, prior studies have suggested l-arginine may help reduce blood pressure and be especially beneficial for people who have just had a heart attack. But before rushing out to purchase l-arginine, however, one should note that prior studies have found that large amounts of l-arginine may be harmful. One such study was stopped early because it was found that those taking l-arginine within 6 months after a heart attack (to improve heart health)  had a much higher rate of death. It should be noted that some of these people were taking mega-doses of l-arginine (up to 9 grams a day).  This is about 2 ½ times the amount found in a typical l-arginine supplement. One popular l-arginine product is a nutrition bar called the HeartBar. The study is notable though because many people will have more than one HeartBar per day.

Preliminary evidence suggests that l-arginine may help improve metabolism, increase muscle mass, reduce fat and decrease blood pressure. But there may still be some question as to the safe upper dosing limit for l-arginine.