Selank and Semax: Heptapeptides in Cognitive Research

Selank and Semax are short synthetic peptides originally developed in Russian research institutes. Both are heptapeptides modified from endogenous regulatory peptides — Selank from tuftsin (an immunomodulatory tetrapeptide) and Semax from a fragment of adrenocorticotropic hormone (ACTH4-10).

In CNS research, both peptides are studied for their effects on neurotransmitter systems, including monoaminergic and GABAergic signalling, and on neurotrophic factor expression, particularly BDNF. Rodent studies have examined anxiolytic-like, nootropic-like and neuroprotective endpoints under stress and ischaemia models.

The molecular basis of these effects is still being characterised. Both peptides cross the blood-brain barrier — partly due to their small size and modified structure — and engage central receptors at low doses. Intranasal administration is the most common route in published preclinical work.

Researchers studying stress, learning and memory often include Selank or Semax as reference compounds alongside classical pharmacological controls. The peptides offer a useful contrast to small-molecule anxiolytics because of their entirely different mechanism of action.

For laboratory use, both peptides are supplied lyophilised. Reconstitution typically uses bacteriostatic water or sterile saline depending on the assay format. Reference-grade material should arrive with HPLC purity verification and a batch certificate of analysis.

Selank and Semax remain research chemicals. This article is an educational reference for laboratory researchers and is not a therapeutic recommendation.