Mouth ulcers are not psychosomatic. And I give the source less credibility because it seems to be promoting MSG. Promotional sources tend to be bias, whether they are right or wrong. Seems obvious. Also, the 2 studies I saw were about MSG's link to headaches. And because there were no links made in the studies of MSG, or possibly glutamate, to headaches, the site seems to suggest they prove no links to any other health effects. Further, the site claims that they have proven MSG has "no side effects" but that's not how science works. "No proven side effects", may be a legit claim, but "proven to have no side effects" isn't. Science doesn't prove negatives and claims in the negative tend to indicate a bias, or worse. You didn't answer my question. Do tomatoes have MSG or glutamate? These are not the same thing. As for experimenting, I'd just rather stay away for lab created flavorings and salts if possible. The body does know the difference. The body has no problem identifying harmful vs helpful bacteria and viruses, it can certainly tell the difference between natural and man made food ingredients. But you eat all you want.