L-arginine is an amino acid that is necessary for the lining of the blood vessels to produce nitric oxide. Nitric oxide allows the blood vessels to relax, thus improving blood flow throughout the body, including to the penis. Studies on L-arginine and erectile dysfunction have used between 2,000-5,000 mg a day in divided doses.ii Supplemental arginine is best taken on an empty stomach.3
If you have symptoms of ED, it’s important to check with your doctor before trying any treatments on your own. This is because ED can be a sign of other health problems. For instance, heart disease or high cholesterol could cause ED symptoms. With a diagnosis, your doctor could recommend a number of steps that would likely improve both your heart health and your ED. These steps include lowering your cholesterol, reducing your weight, or taking medications to unclog your blood vessels.