I've recently tried the L-Arginine + L-Citrulline combo in order to raise nitric oxide as I knew this was the cause of my ED and just WOW - works very similarly to v1agra and it's a much cheaper and safer alternative.

Arginine and Citrulline relaxes the blood vessels and increases overall circulation so this combo would not work for those suffering from performance anxiety but for a lack of nitric oxide, it works beautifully.

I don't take it every day - only before sex.

4 gm of arginine
1 teaspoon (5gm) of citrulline
1 K2 capsule

and voila.

this stuff is awesome.