Herbal medicines containing passion flower or kava extract reduce anxiety studies have shown.
Boffins at the Global Neuroscience Initiative Foundation (GNIF) carried out 24 studies to prove that the amino acids lysine and arginine had the same effect.
Published in the Nutrition Journal, the research points out that St John's wort and magnesium supplements were not effective.
"I don't know what you're talking about," said a GNIF spokesman. "Er - why are you asking anyway? I haven't done anything wrong!
"Who told you to speak to me? Maybe we have been doing some studies... what's that to anyone?
"OK. OK. Let me just have some kava... Why shouldn't I? It's none of your business."