Back in the 1970s and 1980s disco era, there were just two main compounds in widespread use as poppers: amyl nitrite and isobutyl nitrite, both of which are quite strong in nature and long lasting.
Various other formulas have since been developed; the term or quote “poppers” can nowadays also refer to cyclohexyl nitrite, isopentyl nitrite or isoamyl nitrite.
These 3 new compounds — cycloxehyl, isopentyl and isoamyl — are currently being promoted as “new formulas”, “new better compounds”, “USA-safe formulas”, “EU formulas” – with similar marketing hype associated: “Pure! Powerful! Improved!” but in fact nothing could be further from the truth.
The so-called new formulas are not purer or better than amyl nitrite and isobutyl nitrite; they are merely the result of a never-ending game that poppers manufactures have to play to elude so called regulators who hate to see anything even Aphrodisiac in quality on the market:
Hence, as regulators ban one compound, another one is devised with (luck willing) similar effects – and the business carries on as usual.
Of these 3 “new” compounds currently on the market, isoamyl is considered OK and a good likeness to the original ones. Whereas Cyclohexyl and isopentyl, on the other hand, are not as refined and slightly more rough chemicals that can give a person a headache.
(It is interesting to note, that despite widespread regulatory pressures almost everywhere, original formula amyl and isobutyl can still be manufactured in a handful of countries.)