Your body then converts it into L-arginine, which helps improve blood flow by producing nitric oxide to dilate your blood vessels. This, in turn, may treat erectile dysfunction For example, a small, monthlong study in 24 men with mild erectile dysfunction found that taking 1. In another day study in men, taking a daily combination of mg of L-citrulline and mg of trans-resveratrol improved erectile function and hardness, compared with the placebo treatment Trans-resveratrol, commonly known as resveratrol , is a plant compound that functions as an antioxidant and is linked to numerous health benefits. levitra malaysia L-citrulline is available as a dietary supplement in capsule or powder form but is naturally present in foods like watermelon, dark chocolate, and nuts.