I was sure MSG headaches were real until my neighbor from Chengdu did one thing
For a long time I swore up and down that the MSG headaches were real for me, like I'd eat at a Chinese spot in Sunset Park and get a pounding head an hour later, every single time. My neighbor Wei, who grew up in Chengdu, kept telling me it was probably the salt or the oil, not the MSG, but I brushed him off because I knew my own body. Then he made me mapo tofu at his place with a big spoon of MSG straight from the bag and told me to eat it slow, and here's the thing, no headache at all. What got me was the next part, he pointed out that the takeout places I blamed also drown everything in soy sauce and cheap oil, so I started writing down what I ate for two weeks. Turned out the two dishes that really wrecked me were extra salty and greasy, and the plain MSG had nothing to do with it. I still get a heavy feeling after certain spots but now I check the sodium, and honestly it's the same after a bag of chips. Now I'm wondering if other people tested this themselves or if I'm just late to the party, like did anyone actually do the food diary thing and find out it wasn't the MSG?
Your neighbor proved MSG is fine for you in one meal, but that does not mean everyone reacts the same way. Some people really do get flushed or head pain from it, and a single test at home is not the same as a plate of greasy takeout. Writing down your food was a smart move, but ruling out MSG for all of us because it worked for you is a stretch.