Kewpie Mayo is a Japanese mayo that uses egg yolks and MSG in synthesis to create a rich, creamy, umami-filled mayo that I think is superior to the former King of Mayo in my cabinet (Duke's of course). I try to eat mostly natural foods, so if you're like that and the idea of introducing MSG mayo scares you, you might want to read up a bit. It's not really as bad as you thought, and many fancy chefs that are sourcing grass fed beef and locally grown vegetables are seasoning it with MSG, so you might be eating it anyway. Anyway, Kewpie is delicious and worth the indulgence!