Cavallini, G., Modenini, F., Vitali, G., & Koverech, A. (2005, November). Acetyl-L-carnitine plus propionyl-L-carnitine improve efficacy of sildenafil in treatment of erectile dysfunction after bilateral nerve-sparing radical retropubic prostatectomy. Urology, 66(5), 1080-5. Retrieved from http://www.sciencedirect.com/science/article/pii/S0090429505006515
How common is impotence? According to findings from several studies, including “The Massachusetts Male Aging Study,” overall prevalence for men between 40–70 years old is around 52 percent (or around 30 percent of all men between 18–60 years old). That’s right — nearly half of all men over 40 experience erectile dysfunction symptoms at some point. Not surprisingly, research demonstrates that impotence is increasingly prevalent with age. Around 40 percent of men in their 40s experience sexual dysfunction. Up to 70 percent of men in their 70s experience ED. (1) Every year more than 617,000 new cases of impotence occur in the United States alone.
Erectile dysfunction (ED) is the inability to achieve or maintain an erection sufficient for intercourse. Because ED can have a strong psychological component, counseling with a psychotherapist or sex therapist often works. However, more often ED is a symptom of cardiovascular disease and diabetes, both of which can impair blood supply to the penis. In addition, many medications interfere with sexual functioning.
In this study, 78 patients aged 25 to 50 suffering from mild to moderate erectile dysfunction were given this supplement. This study lasted 12 weeks and the size and duration of the erection was the focus of the study. At the conclusion of the study, it was determined that this supplement made a significant difference compared to the controls on parameters like sexual desire, intercourse satisfaction, orgasmic function and overall satisfaction. Side effects were mild and similar to those observed in the control group. Once the trail finished, 90 percent of those taking the VXP supplement wished to continue taking the product because of the impact they observed. 
The truth is medication or psychosexual counselling are the first treatments a doctor will suggest because they’ve been proven to work. If a doctor has approved a medication for you then it’s safe. If you would still like to see if herbal supplements work for you, then there is a list below of supplements thought to work for erectile dysfunction. Just before you invest your money in them, remember they aren’t proven to work:
This African tree bark extract sends blood flow to the genitals, says herbalist Ed Smith, a founding member of the American Herbalists Guild, who adds a warning that yohimbe can cause nervousness and raise already-existing high blood pressure (so avoid taking it if you have heart or kidney disease), and can also negatively interact with antidepressants.
Research is mixed on the effectiveness of acupuncture as an erectile dysfunction cure, but one study published in November 2013 in the Journal of Alternative and Complementary Medicine found that acupuncture can be beneficial for men experiencing erectile dysfunction as a side effect of antidepressants, including selective serotonin reuptake inhibitors (SSRIs) and serotonin noradrenaline reuptake inhibitors (SNRIs).