Nitric Oxide Stimulating Dietary Supplements: Evidence for Effect

Dietary supplements purported to increase nitric oxide production have gained enormous popularity within the athletic (e.g., bodybuilding) community in recent years. Although anecdotal reports suggest a potential benefit from using such products, the scientific evidence is sparse. To the knowledge of this author, only one ingredient consumed in oral form by human subjects has been reported within the scientific literature to promote an increase in blood nitric oxide. This ingredient is a unique form of L-carnitine called glycine propionyl-L-carnitine (GPLC). This article discusses the scientific evidence for nutritional supplements to increase nitric oxide production, as well as the physiological rationale as to why nitric oxide may be important related to athletic performance. Directions for future scientific work in this area of sport supplementation