Watermelon

"Watermelon may be a natural Viagra", I read such news on the web.
Watermelon is rich in an amino acid called citrulline, which will be converted into arginine in the body. Arginine is a precursor for nitric oxide (NO) and this compound is required for blood vessels dilation. I expect that it may be used to decrease blood pressure, but why Viagra ? I am afraid but citrulline may not have such an organ-specific effect like Viagra.
Citrulline was identified from watermelon in Japan. I do not know why journalists accepted such a big mouth by stupid researchers. More importantly, I would enjoy the summer fruit without such an unnecessary effect.