"Pumps" as such can have more aesthetic than anabolic relevance if there are not enough nutrients to flood muscle cells with and the body for protein synthesis. If we refer to "pumps" in an anabolic sense, then it would be unfair to compare insulin to arginine, because insulin is the most anabolic hormone known to science. Even more anabolic than testosterone. Having said that, one may also recall that the precise manner in which the body utilizes insulin for anabolism depends on an individual's level of insulin synthesis (can the body synthesize sufficient insulin; can the body utilize insulin effectively; or are the cells flooded with insulin because of the existence of insulin resistance?). These are questions that may make a direct answer complex. On its own, oral arginine aspartate administration of about 9g daily in three divided doses has been shown to improve insulin sensitivity by promoting nitric-oxide synthesis (evidenced by elevated cGMP levels) and vasodilation (the pre-condition for "pumps") without affecting insulin secretion by the pancreas.Originally Posted by Bato226;
Net, arginine can promote insulin sensitivity and trigger pumps. In the final analysis, though, insulin remains the "king" of anabolism!