Nitric Oxide
What is nitric oxide?
Nitric oxide is a vasodilator that improves blood flow by widening the blood vessels. Having adequate nitric oxide production is vital for maintaining adequate erectile health.
In my previous post, I discussed pharmaceutical options such as Viagra and Cialis for fixing erectile dysfunction. These pharmaceutical options are all PDE5 inhibitors, meaning they increase nitric oxide's effect but do not increase nitric oxide levels. In this post, I will go over supplements that increase nitric oxide levels.
L-Arginine
L-arginine works by increasing levels of nitric oxide in the body. The problem with taking L-arginine supplements is that the supplement is broken down in the digestive system before it can be converted to nitric oxide. Despite that, studies still show that L-arginine improves mild and moderate erectile dysfunction.
Studies show that the ideal dose for improving erectile dysfunction is somewhere between 2g-6g of L-arginine. Any dose <2g is not very effective at improving erectile dysfunction.
L-Citrulline
Like L-arginine, L-citrulline is an amino acid in the body that increases nitric oxide. L-citrulline is converted into L-arginine, which releases nitric oxide in the body as discussed earlier.
Many now prefer to take L-citrulline as it is more effective at increasing L-arginine than directly taking L-arginine supplements. This is because L-arginine supplements have low bioavailability when compared to L-citrulline. In addition to this, L-citrulline is very well tolerated and has fewer side effects than L-arginine.
Studies show that L-citrulline is effective at improving mild to moderate erectile dysfunction. The dosages in studies that showed a significant improvement in erectile dysfunction ranged from 1.5g-3g.
Studies where the dosage of L-citrulline was <1g showed that this dosage was not as effective as taking at least 1.5g of L-citrulline. Studies also show that it can take a few weeks before the benefits of taking L-citrulline take effect.
Beetroot Extract
Beetroots contain nitrates which the body then converts into nitric oxide. Using nitrate-rich food and supplements does not go through the L-citrulline, L-arginine pathway to increase nitric oxide.
Beetroot juice or extract is quickly converted to nitric oxide in the body. L-citrulline has to be converted to L-arginine in the kidneys, which leads to a slower release of nitric oxide and a more sustained and long-lasting increase over time.
There is no guideline or recommended dose that I could find for taking beetroot extract or juice for erectile dysfunction.
Summary
Out of the supplemental options listed above, I would recommend taking L-citrulline to increase nitric oxide over L-arginine. L-citrulline supplementation is more effective at increasing nitric oxide than L-arginine, and I don't know of any reported side effects from taking L-citrulline, unlike L-arginine, which some people report getting headaches from.
L-citrulline lowers blood pressure, as do PDE5 inhibitors like Cialis. Because both L-citrulline and Cialis lower blood pressure, you should consult a doctor before taking both simultaneously. Beetroot extract also increases nitric oxide via the high concentration of nitrates found in beetroots.