Glossary
Nootropic
Giurgea coined the word nootropic in 1972 and set five criteria that most marketed compounds fail. What the term actually means in peptide research today.
Corneliu Giurgea introduced the word nootropic in 1972 for piracetam and related compounds. He defined it narrowly: better learning and memory, learned behaviour that holds up under disruptive conditions, protection of the brain from physical or chemical damage, stronger tonic cortical control mechanisms, and — the requirement most often overlooked — none of the sedative, stimulant or toxic effects usual for psychotropic drugs.
What the label means in a catalogue
Hardly any product sold as a nootropic today meets all five conditions, and the term has no regulatory or mechanistic standing. In the peptide field it is a shelf label that lumps together molecules with completely unrelated targets: ACTH fragments of melanocortin origin such as Semax, the tuftsin analogue Selank, Dihexa derived from angiotensin IV, plus racetam and ampakine-like small molecules. The mechanisms proposed stretch from BDNF upregulation and HGF/c-Met signalling to GABAergic modulation.
Since the group is so mixed, and a large part of the peptide literature consists of Russian-language rodent studies and small clinical series, any comparison should be framed by the type of study, not by the category. None of these substances has US approval.
Related terms and material
neurotrophin · intranasal. Reference material: nootropic peptides, Semax, Selank. Further reading: peptides for focus and memory research.