Racetams

A structural family, not a mechanistic one: everything here is built on the 2-oxo-pyrrolidine acetamide skeleton that piracetam defines. That is where the resemblance ends. Piracetam's own mechanism is still not settled; aniracetam and nefiracetam behave as AMPA receptor modulators; coluracetam acts on high-affinity choline uptake; fasoracetam works on metabotropic glutamate and GABA-B receptors; phenylpiracetam carries a stimulant effect the others do not and is banned in competitive sport for it. Assume nothing transfers between them — a report about one racetam is a report about one racetam.

Legal status is not uniform either: piracetam is a prescription medicine in parts of Europe and an unapproved drug sold as a supplement elsewhere, so whether it is legal depends entirely on where a reader is. The evidence base is thin and largely older than the market selling it, and the headache users commonly report is attributed to choline demand without that having been established.