Mint or Menthol is NOTHING compared to the pain of capsicum. Hell, that stuff burns me put on normal parts of my body. That's why I can only handle Ben Gay or Absorbine Jr.
You've never had homemade peppermint schnapps ice cream, mistaking it for vanilla. I couldn't taste anything for three days.
Some places sell pure capsaicin on a limited basis, and VERY occasionally someone will test it out to see how it works. Pure capsaicin (you literally cannot get any hotter with this chemical) is 16 million Scoville Heat Units. For reference, Tabasco sauce is typically around 2500 SHU. The current record holder for world's hottest chili pepper is a little over 2 million. Pepper spray is 2-5 million.
If you've got a big pot of stew and take a crystal of capsaicin the size of a grain of salt to provide all of the heat for it, it'll make your wife threaten to divorce you (this actually happened to one guy who tested it). It's been described as "smashing your tongue with a hammer" if you try to actually touch a crystal to your tongue.