Also people tend to describe their trips as being subjectively less pleasant.
And please, if you have to resort to dealers, invest in a cheap testing kit. You might be lucky and find a nearby non-profit that can not only do a cheap reactive test, but also a purity test.
Stay safe out there.
EDIT: Sibling comments also mention compounds like 1P-LSD sold online. I'd still test those even if bought from reputable vendors.
Anyways, their safety profiles aren't really that well understood either. They're suspected to be just metabolized into LSD and therefore pretty safe, but they're very new (~2015) and after all they're research chemicals (or rather, not-yet-researched chemicals). In comparison LSD had been known for decades and it's pretty well understood.
I guess this is what prohibition leads to...
I would suggest you learn how to use Tor and surf to some of the many dark net marketplaces that are around.
You can buy an entire sheet of LSD blotter for like $220 atm.
"1P-LSD - PsychonautWiki" https://m.psychonautwiki.org/wiki/1P-LSD