Cortagen

Peptide bioregulators are built on a specific claim: that very short peptides extracted from — or synthesised to match — a particular organ can travel to that same organ and restore its normal function as it ages. Cortagen is the brain-cortex version, promoted for memory, concentration and recovery after head injury or stroke. The proposed route is direct interaction with DNA to switch tissue-specific genes back on. That mechanism has been demonstrated to the satisfaction of the group that proposed it and essentially nobody else.

A tetrapeptide derived from a cortical peptide preparation, reported by the originating group to influence neuronal differentiation markers and to reduce neuronal loss in animal models of cerebral ischaemia. The class hypothesis holds that di-, tri- and tetrapeptides penetrate cell and nuclear membranes and bind directly to specific promoter sequences in double-stranded DNA, modulating tissue-specific transcription — a mechanism supported by molecular modelling and gel-shift work from the originating institute but not independently corroborated. Products are marketed in two chemically distinct forms: "Cytomax" preparations, which are peptide fractions extracted from the corresponding animal organ, and "Cytogen" preparations, which are defined synthetic short peptides. Published clinical evaluation is limited to small Russian studies, generally without blinding, placebo control or independent statistical review.