Why do most psychedelic drugs have such complex chemical formulas?


THC: C21H30O2, LSD: C20H25N3O, Heroin: C21H23NO5

The list goes on.

In: Chemistry

It’s not just psychedelics, most drugs of *all* kinds are complex molecules. For example, penicillin’s molecular formula is C16H18N2O4S. Our body chemistry is incredibly complex. There are many thousands of various proteins, enzymes, and other chemicals interacting with each other to do the things that make us alive. The reason drugs work is that they interact with, alter, or mimic these chemicals in some way.

Think about combinations for locks. If you have 15,000 locks, and only want 1 combination to open 1 lock and none others, a simple 3 or 4 digit combination isn’t going to be enough because you’ll run out of combinations. Some will be simple, like “3” or “65”, but you’ll also wind up with longer combinations like “2954” and “14693”. You need complex combinations to open complex locks.

No of course this doesn’t mean *all* the combinations will have to be complex. some locks will open with a single or double digit combination. Going back to drugs, nitrous oxide is a commonly used anesthetic, and its molecular formula is just N2O.

They don’t really in the grand scheme of things. If you want to get into some really complex formulas (on the surface anyways), look at proteins. For example, titin’s molecular formula is C169,719H270,466N45,688O52,238S911.

I mean, sugar is C6H12O6, that’s pretty complicated. Really, the only thing people deal with on a daily basis that is not complicated is water (H2O).

Many organic chemicals have complex formulas. Mostly beacuse their base structure is a carbon skeleton, which can get more or less arbitrarily large.

Besides that, there is another reason why formulas are less meaningful in organic chemistry: isomers. Isomers are chemicals that have the same formula, but the atoms are arranged in different ways. A prime example:


This can be either [ethanol](https://en.wikipedia.org/wiki/Ethanol#/media/File:Ethanol-2D-flat.svg), which among other things can be freely mixed with water. If you rearrange the atoms, you get [dimethylether](https://en.wikipedia.org/wiki/Dimethyl_ether#/media/File:Dimethyl_ether_Structural_Formulae.svg), whch can only be mixed with water in a limited amount.