I am moving in a couple days and have mayo so I thought it might be interesting to try. To report back, it wasn’t messy to apply at all. Once I got in the shower to rinse it out however, it messed up the shower a bit. Quick spray to cut the grease, all better. It has the strong smell of mayo for sure. Fatty, acidic, eggs. Yes. But my dry scalp loved it. And my hair is ridiculous shiny (let’s see what it looks like dry, though). I haven’t had a cut in a long time and this may have tamed it into submission against the high humidity although I can’t be sure until it’s dry. So far, it feels better for my scalp than Shu Uemura and if you can get past the smell, it feels better for my hair too. I’ll post an update when it’s dry.