You're right, fake LSD is rampant and it's important to screen for it using a reagent test! If this is the case, due to the long comeup I'd suspect the author

You're right, fake LSD is rampant and it's important to screen for it using a reagent test! If this is the case, due to the long comeup I'd suspect the author took a drug in the DOx family. But there's no definitive telltale sign of it, a long comeup can theoretically happen on LSD as well. ^1 LSD analogues (1P-LSD, AL-LAD, ALD-52, etc.) are generally very similar to LSD, to the point where most unknowing users might not know the difference. They are also more expensive to obtain, so they are rarely ever sold as fake LSD. Some of them may even be prodrugs and therefore identical aside from slightly different potency. Most fake LSD will instead be a different class of psychedelics entirely, usually a phenethylamine, such as the DOx class of substituted amphetamine psychedelics, or 25x-NBOMe. 25i-NBOMe is a pretty bad one. Bromo-DragonFLY is said to be utterly horrible. Thank god it's rare. Not all phenethylamines are bad, though, such as 2C-B and mescaline, but the ones sold as fake acid are usually terrible. --- ^1: Something I find extremely fascinating -- different psychedelics are notorious for feeling wildly different to psychonauts, yet when you actually compare two psychedelics, LSD and mushrooms, a lysergamide and a tryptamine, in a double-blind controlled trial you get a list of reported subjective effects that is nearly identical. Can human language not describe the differences, or is it more based on expectation of what you think you are taking more than anything? What if you did the same study but had them write an essay instead of a list of effects? https://www.nature.com/articles/s41386-022-01297-2 https://www.nature.com/articles/s41386-022-01297-2