Selank vs Semax

Selank and Semax are two synthetic heptapeptides developed in Russia and studied for their effects on the central nervous system. They are often grouped together because of their shared origin and similar design, but they are built on different parent molecules and have been investigated for different questions.

Selank is an analog of tuftsin, a short peptide fragment of an immunoglobulin, extended with a stabilizing tripeptide. Semax is an analog of a fragment of adrenocorticotropic hormone, ACTH(4-10), extended with the same kind of stabilizing sequence. Research on Selank has focused largely on anxiety-related behavior and GABAergic signaling in animal models, while research on Semax has centered on neurotrophic factors and neuroprotection models. Neither is an approved medicine in the US. This page compares their structure, mechanisms studied, research areas and lab handling side by side. PRIME supplies both as lyophilized powder for laboratory research use only.

Selank: a tuftsin analog

Selank is a synthetic peptide of seven amino acids. Its first four residues correspond to tuftsin, a short peptide derived from immunoglobulin G that has its own immune-related activity. Three additional residues, a Pro-Gly-Pro sequence, are attached to the end to make the molecule more resistant to enzymatic breakdown.

Selank was developed in Russia, and much of its early literature comes from research groups there. In animal models it has been studied mainly for anxiety-related behavior, and researchers have examined several mechanisms that might explain what they observed. These include modulation of GABAergic signaling, effects on enzymes that break down enkephalins, and changes in immune signaling molecules, reflecting its tuftsin origin.

Research areas that have been investigated include:

• Anxiety-related behavior in rodent models
• Stress response
• GABA receptor system modulation
• Enkephalin metabolism
• Immune and cytokine signaling

Selank is a research compound and is not an approved medicine in the US. Much of the published work is preclinical, and independent replication outside its country of origin is limited, so findings should be read with that in mind.

PRIME supplies Selank as a lyophilized powder for in-vitro and preclinical research. It is sold for laboratory research use only and is not for human consumption.

Semax: an ACTH fragment analog

Semax is a synthetic peptide of seven amino acids. It is based on a fragment of adrenocorticotropic hormone (ACTH), specifically the ACTH(4-7) sequence, extended with a Pro-Gly-Pro tail for stability, and it is usually described as an ACTH(4-10) analog. Unlike full ACTH, this fragment is not associated with the hormone's main action of stimulating the adrenal glands.

Like Selank, Semax was developed in Russia, and much of its literature originates there. Research has focused on the brain, particularly on neurotrophic factors. Studies in rodents have examined changes in the expression of brain-derived neurotrophic factor (BDNF) and related signaling, as well as effects on neurotransmitter systems such as dopamine and serotonin.

Research areas that have been investigated include:

• BDNF and neurotrophic factor expression
• Neuroprotection in models of cerebral ischemia
• Learning and memory models in animals
• Gene expression changes in brain tissue
• Dopaminergic and serotonergic signaling

Semax is a research compound and is not an approved medicine in the US. As with Selank, most evidence is preclinical and much of it comes from a limited number of research groups.

PRIME supplies Semax as a lyophilized powder for in-vitro and preclinical research. It is sold for laboratory research use only and is not for human consumption.

Although they share an origin and a stabilizing design, Selank and Semax point toward different research questions. In both cases the evidence is mostly preclinical, which suits them to animal and cell model work.

Selank fits studies of anxiety-related behavior, stress response and GABAergic modulation in animal models, as well as work at the boundary of the nervous and immune systems, reflecting its tuftsin parent molecule.

Semax fits studies of neurotrophic signaling, particularly BDNF expression, and neuroprotection models such as cerebral ischemia, along with learning and memory models in animals.

Some study designs include both to contrast the behavioral and neurochemical profiles of two peptides built on the same stabilizing strategy. For full background, read the Selank research guide and the Semax research guide. Another peptide studied in the context of the nervous system is covered in the DSIP research guide. Every batch has a published certificate of analysis on the lab results page.

For laboratory research use only. Not for human consumption.