What Does Arginine Do For Bodybuilders?

Arginine is an amino acid that functions as a precursor to nitric oxide in your body. According to the New York University Langone Medical Center, nitric oxide relaxes your blood vessels and may aid in a variety of bodily functions, such as cell division and boosting your immune system. While fitness nutrition companies may promote arginine as a proven supplement to improve muscle growth, the research into its use for bodybuilding purposes is largely inconclusive as of this publication.

Growth Hormone

Associate Dean at the Department of Exercise Science, University of Massachusetts, Priscilla Clarkson states that early research into arginine and other amino acid supplementation demonstrated a potential for growth hormone increases, but these studies had flawed methodologies. Subsequent research in the early 1990s with arginine failed to demonstrate a significant increase in growth hormone through manufacturer-recommended doses. However, more recent double-blind and placebo-controlled research has shown that a combination of arginine and the amino acid ornithine may increase growth hormone levels with regular strength training. Due to the inconclusive nature of this research, it is unclear if arginine actually increases your growth hormone levels.

Immune System

A properly functioning immune system is crucial for a bodybuilder to remain healthy and to conduct an intense strength training program. There are some tenuous links between arginine supplementation and improved immune system function. One such study demonstrated arginine's ability to reduce the occurrence of colds in children, while another showed a potential link between arginine and positive immunological response in older individuals vaccinated against Streptococcus pneumoniae. However, there has not been a direct study of arginine supplementation and immune system response in bodybuilders.

Steroids and Hypertension

Clayton South, a certified specialist in performance nutrition by the International Sports Sciences Association, states that bodybuilders who are recovering from androgenic or anabolic steroid use may benefit from arginine supplementation. Arginine is potentially helpful to these bodybuilders because discontinued use of these steroids leads to hypertension. Some small trials have shown arginine doses around 12 g per day will reduce blood pressure, but conclusive research on this aspect of arginine is ongoing.

Side Effects

The medical community generally considers arginine safe for human consumption, even in high doses up to 20 g per day. Arginine may have negative interactions with some types of medications, including lysine for herpes treatment, NSAIDs and medications that affect your potassium balance. Heavy doses of arginine may also lead to nausea and diarrhea when taken to excess. South notes that many protein supplements used by bodybuilders already contain arginine, so you should carefully monitor your daily intake and speak with your physician before taking additional arginine as a part of your weight training nutrition program.