Remember back to the late 1990s when former politician Bob Dole took our country (and airwaves) by total surprise when he promoted a then little-known drug called Viagra? Not only was erectile dysfunction (ED) rarely discussed among doctors and patients, it was never mentioned on TV! In those ads, Dole specifically discussed how his prostate cancer and subsequent treatments left him with ED.
Fortunately, today, much of the stigma surrounding ED has dissipated, in that many men are more comfortable discussing erectile problems with their doctors. After all, according to Harvard Health Publications, this common condition affects approximately 30 million American men1, and ED drugs such as Viagra and Cialis are easily accessible. And they work.
But there is a natural alternative to look into.
Boost Blood Flow Naturally
L-citrulline is a naturally occurring amino acid. The body converts L-citrulline to another amino acid, L-arginine, which is responsible for enhancing blood flow throughout the body. It does so by creating nitric oxide (NO), a compound that widens blood vessels. As such, both of these amino acids have been shown to benefit the heart by lowering the risk of clogged arteries and heart disease. NO is also a signal produced by the body that is essential to cause an erection.
I don’t want to get too complicated, but I believe it is important that I describe a little bit about the pharmacology of these amino acids in the human body so you understand how they work. Supplements have been developed to increase circulating L-arginine to enhance NO, but there is a major problem; L-arginine is efficiently broken down by intestinal or liver metabolism. However, L-citrulline largely escapes this breakdown and enters the kidneys where it is rapidly converted into L-arginine. So oral L-citrulline supplementation increases L-arginine, which then augments NO signaling, including blood flow into the penis.
Taken together, this is an area of research that I call “promising but not proven.” The science makes complete sense, and there are a several small human clinical studies that support the effectiveness of this approach. One study found that supplementation with L-citrulline led to an improvement in endothelial dysfunction (problems with blood vessel constriction and dilation caused by the diminished production or availability of NO).2
This same mechanism of action also helps ease ED symptoms. The L-citrulline–to–NO pathway enhances blood flow to the genitals, working almost like a “natural Viagra.”
Another trial examined the safety and effectiveness of L-citrulline on erections in patients with mild ED. Twenty-four men received placebo for one month, then L-citrulline the following month. Oral L-citrulline supplementation for one month was able to improve erection hardness enough to restore normal penis function in 12 of 24 patients with mild ED. Specifically, improvement in erection firmness went from a score of 3 (mild ED) to 4 (normal function) in participants taking L-citrulline. This was a highly statistically significant improvement. All of the men who experienced better erections reported being very satisfied. The researchers concluded that L-citrulline may serve as an alternative treatment for mild to moderate ED, especially in men who prefer not to take prescription meds due to their side effects (which include headaches, vision changes, stuffy/runny nose, and flushing).3
L-arginine alone has been studied and shown to boost NO and erections in men as well.4 However, the problem with arginine is that, as described above, when taken orally, it gets broken down, so it takes high doses.
I hope research into the many of the potential benefits of L-citrulline continues to evolve. You can be assured that I will continue to follow it closely.
