Oral L-Arginene before resistance exercise blunts growth hormone effects

Came across this study the other day and I thought it was interesting. Almost every preworkout over the last 15 years have contained some form of Arginine. It was the original vasodilator and was in every "NO" product. We now have much better options for a pump. The researchers in the study found something that should confirm to supplement companies that Arginine shouldn't be used in preworkouts anymore.

Trained athletes who ingested 6g of Arginine before working out had a 41% decrease in GH and IGF-1 levels postworkout. Your body naturally releases GH and other growth factors after a workout to help repair and rebuild muscle tissue. Taking Arginine before a workout may significantly hinder your body's natural anabolic response to training! Worth noting-it's my theory that citrulline may have a similar effect, as the study measured plasma Arginine levels, and citrulline also increases plasma arginine levels. Just a theory, more research is needed.