Arginine and Erectile Dysfunction

Erectile dysfunction is often considered as one of early signs of vascular disease (see last week’s post) due to its high prevalence in patients with cardiovascular problems. Indeed, evidence indicates that deficiency in endothelial factors contribute to micturition disorders, especially in erectile dysfunction. By far, the most important endothelial factor is nitric oxide, which is formed from arginine with the help of nitric oxide synthase. Two possible causes of such a deficiency are plasma and tissue lack of key substrates (mainly arginine) combined with increased levels of endogenous inhibitors of nitric oxide synthase (ADMA) (i.e., Sánchez A1, Contreras C, Martínez MP et al. PLoS One. 2012;7(4):e36027 ).

Consequently, the semi-essential amino acid arginine has been studied as a nutritional treatment in mild erectile dysfunction – both in laboratory animals and humans. In the newest double-blind, placebo-controlled, two-way crossover randomized clinical trial (the most sophisticated testing method applied to humans); twenty-six patients with mild erectile dysfunction received eight grams of arginine with or without conventional medicines. The results showed that the oral administration of arginine (with aspartate-adenosine monophosphate) was effective, very well tolerated and could be used as a safe first-line therapy (Neuzillet Y, Hupertan V, Cour F et al. Andrology 2013;1(2):223-228). Similarly, the positive role of arginine was demonstrated in sixty-one patients who had blood ratio of arginine to ADMA, which is an inhibitor of nitric oxide synthase, substantially lower when compared to controls. This study indicated that elevation of arginine causally contributed to the disease treatment (Paroni R, Barassi A, Ciociola F et al. Int J Androl. 2012;35(5):660-667).

Another study conducted with fifty-four erectile dysfunction patients in Italy found that three months of arginine treatment led to a small, but statistically significant improvement in total and single parameters of the disease. The authors concluded that, “the favourable cardiovascular effects of nutraceuticals might also reflect on male sexual function with possible implication in the treatment and prevention of erectile dysfunction” (Gianfrilli D, Lauretta R, Di Dato C et al. Andrologia. 2012;44 Suppl 1:600-604). Similar results were obtained with Japanese patients (Aoki H, Nagao J, Ueda T et al. Phytother Res. 2012;26(2):204-207).

Most importantly, ISSM Standards Committee for Sexual Medicine (Porst H, Burnett A, Brock G et al. J Sex Med. 2013;10(1):130-171) recently made a rigorous and newly updated overview on currently used and available conservative treatment options for erectile dysfunction with a special focus on their efficacy and tolerability. Oral administration of arginine (3-5 g) alone was recognized as a level 2 treatment, and orally applied arginine in a combination with appropriate medicines as the highest (level 5) treatment for the disease.