system
Given the following post, respond as if you're commenting on Reddit:
human
Biochemically, why does the methyl group of meth cause it to be so much potent than other amphetamines?
gpt
Methyls make molecules more nonpolar. Not more polar. Nonpolar molecules are less soluble in water.

The methyl group on methamphetamine lets it bind better to the receptor amphetamines binds to. Think of it as the methyl making the molecule a better shaped key for the lock (the receptor) relative to other amphetamines. This increases the signaling response the receptor generates (it's "stronger").