As the saying goes: “the dose makes the poison”. Many (perhaps most) drugs cause harm at the wrong dosage.
Not only drugs, almost everything is bad at the wrong dosage. Case in point: water.
What about prions, or strange matter?
and I think talking about breaking molecular bonds though or bringing "fundamental forces" into this is misleading and disingenuous. the point of the OP is to say, "you can take anything in a small enough dose and its not poisonous"
And when you say prions or whatever like you were, my point is if you take small enough doses even of those, you won't be poisoned. you get what I mean, so lets not waste each others time on trying to confuse impossibilities with reality. you won't be getting hurt or die or meaningfully poisoned by ingesting one "prion" or particle of "strange matter". and now when you describe any "poison" with this model, say you ingest 1 particle of even a pure poison, you won't be getting hurt or die.
It was a joke.
That said, the state of mind must be so wild that "is it poisonous in this specific/usual sense" is probably not the right thing to discuss.
I've struggled to tell the difference between doses of LSD that exceed 100µg. Maybe I just take it too frequently to make much of a difference. It's also possible that it only increases duration, but not intensity.