74% of erectile dysfunction patients improved with L-arginine intake

Intake of the amino acid L-arginine could help men with the most common form of erectile dysfunction (ED), known as vasculogenic ED, according to the findings of a trial published in the May 2022 issue of the Journal of Endocrinological Investigation.1 Vasculogenic ED is caused by reduced blood flow to the penis, generally related to vascular disease and endothelial dysfunction. An amino acid, arginine, is needed for the formation of nitric oxide, a molecule that relaxes the blood vessels, including the vessels that deliver blood to the sex organs.

The study included 95 men aged 20 to 75 years with ED. Participants received two grams of L-arginine three times per day or a placebo three times daily for three months. Their penile blood flow and testosterone levels were measured, and participants completed the International Index of Erectile Function six question (IIEF-6) patient questionnaires at the beginning and end of the trial. Among patients taking arginine, 74% experienced an improvement in ED degree as categorized by questionnaire responses, while only 18% of the placebo group experienced improvements. Additionally, at study completion, 24% of the men taking L-arginine had IIEF-6 scores that showed they no longer were diagnosable with ED.

The authors concluded that L-arginine could be an alternative treatment for men with mild to moderate vasculogenic ED who experience adverse effects from drugs that are customarily prescribed for their condition or who cannot otherwise take them.


Apply What You've Learned: L-arginine

  • L-arginine is an amino acid made in the body from citrulline, another amino acid. It occurs in foods that include nuts, grains, meat and dairy products. Although L-arginine can be made in the body, studies have shown increased intake may be useful in certain conditions related to inadequate blood flow like ED.2
  • Because it is necessary for the production of nitric oxide (which enables the blood vessels to relax), L-arginine may be helpful for people with cardiovascular disease.3
  • L-arginine could help improve exercise performance and recovery through several mechanisms, making it popular among athletes and body builders.4
  • L-arginine may also support immune function and wound healing.5,6 It may additionally be helpful to individuals with Raynaud’s syndrome (also known as Raynaud’s disease or phenomenon) where there is poor blood flow to the extremities like fingers and toes.7


  1. Menafra D et al. J Endocrinol Invest. 2022 May;45(5):941-961.
  2. Böger RH, Bode-Böger SM. Annu Rev Pharmacol Toxicol. 2001;41:79-99.
  3. Yin WH et al. Clin Nutr. 2005 Dec;24(6):988-97.
  4. Campbell BI et al. J Int Soc Sports Nutr. 2004 Dec 31;1(2):35-8.
  5. Lindez AAMI et al. Cell Mol Life Sci. 2021 Jul;78(13):5303-5324.
  6. Schneider KL et al. Adv Skin Wound Care. 2019 Oct;32(10):457-462.
  7. Curtiss P, et al. J Eur Acad Dermatol Venereol. 2019 Mar;33(3):497-503.

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