I thought it was 16 million, not 1 million, so it's still not quite there yet.

You’re mistaken. Pure capsaicin is 16 million SHU. I can’t remember the exact details of how the SHU is defined, but IIRC it’s related to the number of times a substance (having been dissolved in alcohol) would have to be diluted in a solution of sugar water before the pungency is undetectable.

It's the dilution until pungency equals that of water / cannot be detected by a taste panel.

As Ed explains at 5:40 in the video [1] above, they use a high-performance liquid chromatography (HPLC) test [2] rather than a subjective taste panel now.

[2] https://en.wikipedia.org/wiki/Scoville_scale

Pure capsaicin is 16m Scoville. Not aware of any peppers using chemicals other than capsaicin, though you are correct that other chemicals supersede capsaicin on the Scoville scale.

In the hot ones video the breeder said that there are indeed other capsinoids present and that it is key to the experience.

Obviously he does have an incentive to say that! But when someone says "no, plant chemistry is more complicated than that" I'm normally inclined to believe them!

Does this mean that the highest any new "hot pepper" can ever get to is 16m Scoville?

There is a euphorbia (a hoodia? can't recall reference) with a chemical 500 times stronger than capsaicin. IIRC so strong it destroys the receptor.

Anyone have a ref while I paw through my memory slowly?

Bonus: RTX has also previously been investigated as a treatment for lifelong premature ejaculation (PE).. Volunteers for clinical trials, anyone?

Jesus. I hope that's administered while you're in an induced coma.

Someone actually concentrated and taste tested some of this in a fairly scientific process, and it actually didn't end up being as hot as expected. iirc the molecule is too big to properly bind to receptors the way capsaicin can.

https://www.youtube.com/watch?v=XPe2bssalOY