Very close / the same in my experience. I've never had the exact same effect even from two doses of LSD from the same sheet, much less different producers, but 1p-lsd was just fine and felt the same to me.
I bought a bit before it was put on the controlled substances list in my country. A good demonstration that legal LSD doesn't end the world: it was legal, it was LSD, the world didn't end!
>I've never had the exact same effect even from two doses of LSD from the same sheet...
As a retired neurosurgical anesthesiologist (38 years) who has never taken LSD or any psychedelic/psychoactive substance, I found your observation very thought provoking.
More likely than not, the LSD on each unit on a given sheet is chemically identical.
Therefore, the only variables are 1) the amounts in each dose, and 2) the substrate on which the drug will act (i.e., your brain at a given instant is — on the whole — the same, but functionally totally different from second to second as pathways activate and connect).
I would therefore hypothesize that, more likely than not, most if not all individuals who have a strong response to a given dose of LSD will have different responses to repeated doses from the same sheet.
I'm hoping people who've taken LSD will school me.
I think it's important to differentiate between the effect of LSD and the experience of the subject. The effect is always the same (for the same dose) but the experience is different. The differences in experience come because LSD is just a modifier on your perception and thoughts. Thus you can only have the same experience if you repeat the same sensory inputs and thoughts - which is pretty much impossible.
LSD has quite a bit of subjective experience change based solely on mood, set, and settings. Although beyond that, everyone's reality is not the same as the next guy. Aside from that, repeated dosing of anything at all can be different from dose to dose based on body chemistry, tolerance, hormone balance, and dopamine/adrenaline type of responses. Mood plays a large factor in this as well. Tylenol does not work the same way at the same dose in each and every person, either.
I bought a bit before it was put on the controlled substances list in my country. A good demonstration that legal LSD doesn't end the world: it was legal, it was LSD, the world didn't end!