Most drugs/medicines are taken in higher doses because the body filters or neutralizes the compounds so much that only a small portion gets into the blood.

That's still different.

Even if the total quantity of the drug is small in the system once it gets there, it's not the same as how LSD works. The drug, likely because of its similarity to serotonin and size , is readily absorbed into the blood stream and passes the blood brain barrier easily. It is not filtered out to a small percentage of it's original dose like most drugs/medicines.

You surely are aware of this ?

There are very few drugs that can work in small dosages like LSD. As I said, fentanyl is one.

Drugs like DMT /Ayahuasca also can't be ingested unless they are mixed with a maoi inhibitor.

Most psychedelic research chemicals (nbome) are much different than lsd with different pharm and effect properties.

It's possible that LSD is released more quickly on the tongue than nbome drugs. So as soon as it hits the tounge the drug is delivered. I don't think there is research on this. But I'll look into it. I do know that the first trip was caused by a small contact of the drug on someone's hand. That the cleaned off immediately. And it was enough time to absorb a substantial amount of the drug.
I heard women would put on lipstick and smear LSD on the front and kiss police during protest to dose them. If That happened it might support a very fast delivery.
I can't find the source right now to verify the story. I'll keep looking. Maybe I have details wrong. Maybe it was Charles Manson instructing women to do this. Does this story sound familiar to anyone ? I'll have to find the source and verify.

But my point is.

This idea that it's not neutralized in the stomach is false. There is plenty of research on that.