Well I guess hotness is somewhat objective, but since there exists manythings sweeter than sugar, I wondered if anyone had found a chemical hotter (spicier) than capsaicin? A google search for “hotter than capsaicin” gives two results mentioning 1000 times hotter than capsaicin but neither can be accessed to find out what substance they are describing.
I used to work with a chemical engineer who was really into hot foods and started his own internet hot sauce shop. I learned that capsaicin has a very special property of triggering human nerves to feel heat without destroying them. He found many hot sauces that were indeed hotter than capsaicin but they all left burns, one time so bad he could not eat anything other than cold milk products for several days.
So maybe the question you might be asking is there anything hotter than capsaicin that is edible and doesn’t kill or maim you? So far as he knew, no. But in my experience try putting some Icy-hot or Ben-gay in your mouth, they are not edible but they are hot.
Here is the pertinent quote (about dead center of pg 7 of the PDF):
Isn’t stevia supposedly sweeter than sugar?
A tangential question: What makes mustard and horseradish “hot”?
“Vanilloid receptor agonist” gives a lot of sources including http://www.komabiotech.co.kr/product/neuro/category/vanilloids.htm . Seem to suggest Resiniferatoxin (RTX) is pretty much the hottest.