I wouldn't recommend inhaling an extract of any hot pepper. There are plenty enough questionable flavorings in circulation, I would never offer an irritant like Capsicum in an e-liquid. The stuff will burn your eyes, mouth, and even your skin. It can be tolerated in the stomach, in moderate amounts, but look at the environment of the stomach... I don't think the lungs would appreciate a pepper extract, personally.
I'm not saying don't do it, I'm just saying I would never recommend it.
Caution is always a good thing, no doubt about that - for sure and for certain.
From ECX's HEAT page:
Capsicum is derived from the American pepper plant
INCORRECT! (and I should have noted it earlier in all my posts

). Capsicum is the genus of a plant. Capsaicin is the 'hot chemical' that's extracted from a pepper in the Capsicum family. So we're talking about inhaling diluted Capsaicin.
Fwiw, we're herbalists - and we make around 40-50 gallons of various 'cayenne tinctures' yearly (as well as taking it internally, using it along with other herbs in a (very diluted) eyewash, and for therapeutic baths) - so we're familiar with the coughing & burning that can come inhaling intensely concentrated fumes - and the temporary burning sensations.
However, capsaicin only gives the 'sensation of burning' - unlike garlic, mustard, ginger, etc., it does not cause actually tissue damage if used in excess. Of course, it can cause redness from the irritation - and those that are allergic to any of the phytochemicals in the natural plant, may develop tiny blisters from prolonged contact.
'No doubt about it ---
Capsicum that's extracted/isolated/purified from a natural plant is a throat/lung irritant which causes TH.
Nicotine that's extracted/isolated/purified from a natural plant is also a throat/lung irritant which causes TH.
Either used 'in excess' or irresponsibly will cause intense coughing & burning.
One used 'in excess' or irresponsibly can cause death.
I don't think the lungs would appreciate a pepper extract, personally
I am sure our lungs don't appreciate either one - or any other 'flavor chemical' that increases irritation (TH). Of all the "chemical irritants" that produce TH, it's my opinion that an isolated/purified extract of capsicum is unlikely to cause any type of damage. But that's just an opinion (based on never hearing of, or experiencing any lasting-negative-issue from inhaling 'cayenne fumes' - and a few 'studies' I surfed through
years ago).
So, I says to myself, start Googling 'capsaicin inhalation' and see if you can find any
current studies or data. BINGO! Apparently 'capsaicin inhalation' is used in something called "capsaicin cough challenge" in clinical research because it induces cough in a dose-dependent and reproducible manner. (The amount we used/suggested does NOT cause us to cough, or to feel to feel anything different that the common TH we feel from nic).
From here:
Safety of capsaicin cough challenge testing
RESULTS:
One hundred twenty-two published studies since 1984 described 4,833 subjects (4,374 adults, 459 children) undergoing capsaicin cough challenge, with no serious adverse events reported. Subjects included healthy volunteers as well as patients with asthma, COPD, pathologic cough, and other respiratory conditions. Minor complaints described in a small fraction of studies consisted mainly of transient throat irritation. Personal communication with the authors of > 90% of the studies confirmed an absence of any serious adverse events. Furthermore, these investigators have performed thousands of additional capsaicin challenge studies not reported in the literature, also without any associated serious adverse events.
CONCLUSIONS:
A review of the 20-year clinical experience has failed to uncover a single serious adverse event associated with capsaicin cough challenge testing in humans. Given the need for better antitussive therapies, capsaicin represents a vital component of future scientific inquiry in the field of cough.
Levitas, even though you may not have intended to 'challenge me' personally, I appreciate the opportunity to check my experiences & opinions against known research. My ego probably wouldn't have been to happy if I would have found dozens of studies that disagreed with my opinion, but I can take anything I can dish out (and besides, being able to replace a wrongful opinion/belief with something 'more right' is always a goodness - no matter how stupidly my ego responds initially).
Of course, "clinical studies" (particularly those funded by the government) are never the be-all-end-all for finding & assessing the Truth of anything. But that's an entirely different post/subject.
If everyone would 'challenge more often' (respectfully of course, as you/others are such good examples of on ECF), we'd all end up learning & solving even more than we already do!
(Btw, 'getting ready to mix up your French Vanilla/Black Honey recipe tonight ...and we haven't even tried the Black Honey 'alone' yet. It sounds terrific! We'll be mixing up a couple of 'singles' of the BHT, too. 'Any suggestion for percentage on the Black Honey as a stand-alone?)