HHC
The Howard Hughes Corporation
stock NYSE

Nice! With some molecules you get chirality and other factors where, you maybe ended up with all S-isomer and non R-isomer, so even though it is "pure" you have two distinct molecules present at various quantities that can change batch to batch (HHC and derivatives are a good example of this, afaik, HHC, HHCp, HHCo, HHCpo, and HHCv all have this chirality issue) - more people are probably more familiar with this from ketamine, but LSD also can have inactive stereo isomers - I think there are over a dozen biologically inactive stereoisomers of LSD... 16 to be exact since I just looked up that it has 4 chiral centers.
The degradation of LSD is often these molecules being formed - so, you might be able to say that 100ug of LSD isn't always 100ug of LSD. If it has degraded, you start to form inactives like iso-LSD, LSD-n-Oxide, and who knows what else forms from lumiscent degradation) - I don't think you can accidentally end up with nor-LSD or 2-oxo-LSD (both of which are metabolites) through a bad synth, or that you might end up with some Lysegeic Acid itself left over (it just seems highly unlikely and/or impossible, but given that there are 16 stereoisomers of LSD and I know know a couple that can form during synthesis, I could be lacking some knowledge in this particular category (somebody else might chime in).
From my understanding, all of those other things you can accidentally have left over are going to be inactive, but in the case of this discussion, it could be that one batch of LSD or another just had different ratios of expressed isomers present - it isn't beyond the imagination to consider, but most people actually doing a real synth for LSD are going to be stereoselective and careful not to form these isomers at an early stage (but not starting with a racemic mixture), or will clean it up at a later phase and not accidentally introduce those isomers.
This could be a valid scientific explanation as to why one crystal of LSD feels different than another, but given that the other molecules are inactive, it would only explain a POTENCY difference, not a quantifiable difference in actual effects.
Perhaps, some of these isomers have unstudied metabolites that *are* active. I think we may have heard of them, but they could also be similar to weak or mildly active LSD metabolites and then overlooked by the scientific community as having a negligible impact - even if that 0.1% is iso-LSD and iso-LSD produces nor-LSD when metabolized at some appreciable rate (I don't think this is true, I am just throwing it out there as an example), I, personally, don't find it sufficient to explain the "differences".
One of the great mysteries, I guess.

Nice! With some molecules you get chirality and other factors where, you maybe ended up with all S-isomer and non R-isomer, so even though it is "pure" you have two distinct molecules present at various quantities that can change batch to batch (HHC and derivatives are a good example of this, afaik, HHC, HHCp, HHCo, HHCpo, and HHCv all have this chirality issue) - more people are probably more familiar with this from ketamine, but LSD also can have inactive stereo isomers - I think there are over a dozen biologically inactive stereoisomers of LSD... 16 to be exact since I just looked up that it has 4 chiral centers.
The degradation of LSD is often these molecules being formed - so, you might be able to say that 100ug of LSD isn't always 100ug of LSD. If it has degraded, you start to form inactives like iso-LSD, LSD-n-Oxide, and who knows what else forms from lumiscent degradation) - I don't think you can accidentally end up with nor-LSD or 2-oxo-LSD (both of which are metabolites) through a bad synth, or that you might end up with some Lysegeic Acid itself left over (it just seems highly unlikely and/or impossible, but given that there are 16 stereoisomers of LSD and I know know a couple that can form during synthesis, I could be lacking some knowledge in this particular category (somebody else might chime in).
From my understanding, all of those other things you can accidentally have left over are going to be inactive, but in the case of this discussion, it could be that one batch of LSD or another just had different ratios of expressed isomers present - it isn't beyond the imagination to consider, but most people actually doing a real synth for LSD are going to be stereoselective and careful not to form these isomers at an early stage (but not starting with a racemic mixture), or will clean it up at a later phase and not accidentally introduce those isomers.
This could be a valid scientific explanation as to why one crystal of LSD feels different than another, but given that the other molecules are inactive, it would only explain a POTENCY difference, not a quantifiable difference in actual effects.
Perhaps, some of these isomers have unstudied metabolites that *are* active. I think we may have heard of them, but they could also be similar to weak or mildly active LSD metabolites and then overlooked by the scientific community as having a negligible impact - even if that 0.1% is iso-LSD and iso-LSD produces nor-LSD when metabolized at some appreciable rate (I don't think this is true, I am just throwing it out there as an example), I, personally, don't find it sufficient to explain the "differences".
One of the great mysteries, I guess.