According to the National Health Institute (NIH) Consensus Development Panel on Impotence, erectile dysfunction (ED) is defined as the persistent inability to achieve and/or maintain an erection sufficient for satisfactory sexual performance.

Causes of erectile dysfunction may be psychological and physiological factors (neurogenic, vascular, endocrine causes). It may also be a side effect of drugs and a symptom of health complications such as diabetes.

Penile erection occurs as a result of increased blood inflow to the penis, engorgement with blood, and decreased outflow of blood from the penis. Primarily, this process is mediated by nitric oxide, which is a neurotransmitter and vasodilator. Nitric oxide is synthesized from L-arginine.

Several researches on the efficacy of L-arginine and nitric oxide on penile erection, fixing erectile dysfunction, have reported positive effects of both chemicals in stimulating and maintaining erection. For example, a study reported that 80 % of men (out of 40, age group 25 – 45) with erectile dysfunction treated with L-arginine (dosage: 1.7 g/ day) and Pycnogenol, an extract from French maritime pine bark (Pinus pinaster), (dosage: 80 mg/day) recovered from their erectile dysfunction after one month of treatment. Pycnogenol, also an antioxidant, stimulates synthesis of nitric oxide from L-arginine. The researchers reported that there was no side effect associated with the supplements.

In another double-blind, placebo-controlled, clinical research on the effect and safety of the combination of 6 g of L-arginine glutamate and 6 mg of yohimbine hydrochloride with that of 6 mg of yohimbine hydrochloride alone and that of placebo alone, for the treatment of erectile dysfunction (ED), it was reported that combined oral administration of the L-arginine glutamate ( 6 g) and yohimbine (6 mg) was effective in improving erectile function in patients with mild to moderate erectile dysfunction (ED).

 

Herbs and sexuality:

Yohimbe: health benefits and side effects
Ginseng: health benefits and side effects
Ginkgo Biloba: health benefits and side effects

Erectile dysfunction related articles:
What is erectile dysfunction? How does erection occur?
What are the causes of erectile dysfunction?
What are the treatments for erectile dysfunction?


References:

Stanislavov, R. and Nikolova. 2003. Treatment of Erectile Dysfunction with Pycnogenol and L-arginine. Journal of Sex and Marital Therapy, 29(3): 207 – 213.

Basu, A. and Ryder, R. E. J. 2004. New Treatment Options for Erectile Dysfunction in Patients with Diabetes Mellitus. Drugs, 64(23): 2667 – 2688.

Toda, N. Ayajiki, K. Okamura, T. 2005.  Nitric Oxide and Penile Erectile Function. Pharmacology and Therapeutics, 106: 233 – 266.  

Lebret, T., Hervéa, J. M., Gornyb, P., Worcelc, M. and Botto, H. 2002. Efficacy and Safety of a Novel Combination of L-Arginine Glutamate and Yohimbine Hydrochloride: A New Oral Therapy for Erectile Dysfunction. European Urology 41(6): 608-613.