Sorry to hear that. Food research is super hard. Lots of people definitely have sensitivities to foods (like gluten) that have real effects whose mechanisms are not well understood. e.g. epilepsy is often really well controlled by a keto diet - wtf?

Understanding your own body and managing your diet accordingly is a great thing to do. Sad that it sometimes gets attacked as unscientific. Just because scientists looked for a broad food mechanism and didn’t find it doesn’t mean these effects aren’t real.

AFAIK there are few rare occurrences where MSG can cause reactions akin to an allergy. It's not an allergy per se given that there's no immune reaction involved though.

This phenomenon is rare but well documented, albeit not very understood. Sucks though.

Is there a chance you are sensitive to the sodium part of MSG?

I believe that, in addition to the blood pressure issues some people have, some react quite strongly to higher salt levels in food.

I eat salt regularly, so probably not, and I can eat other (softer) cheeses, and I can eat potato chips but not flavored ones with MSG (this was actually how I discovered MSG might be a trigger). So I am very confident that it has to do with glutamate.

OK, fair enough. It was just something I was pondering.