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Need a professional opinion on whether Semax or Selank is the better nootropic peptide for your research studies? This all-inclusive article will show you the ins and outs of these two cutting-edge peptides so you won’t have to look elsewhere. There are several key differences between the nootropics Semax and Selank, even though they are structurally identical and have comparable research potential. Studies suggest that Semax may have strong neuroprotective and gastroprotective characteristics, while Selank is speculated to have anxiolytic potential. This guide helps researchers choose which peptide is worth further investigating by summarizing these commonalities and differences according to the needs of the study.

Semax Peptide: What is it?

 Semax is a peptide synthesized from a 4-amino acid segment (Met-Glu-His-Phe), and a 3-amino acid segment joined at the C-terminus. Adrenocorticotropic hormone (ACTH) and all melanocortin hormones share the Met-Glu-His-Phe segment in their sequence. Nonetheless, it has little to do with the hormonal impacts on the endocrine system. Because of the inclusion of Pro-Gly-Pro, Semax is reputedly now more stable and has been hypothesized to penetrate the blood-brain barrier, allowing it to impact the central nervous system (CNS). 

According to early research, Semax seems to promote neuronal development, survival, and maintenance via its interactions with several neurotrophic factors. Developed in the 1980s, the peptide was intended by researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences to be used in studies related to neuroprotective and cognitive-enhancing approaches in ischemic stroke, encephalopathy, and optic nerve atrophy. 

The peptide seems also to have nootropic impacts. N-Acetyl Semax Amidate is another name for acetylated and amidated Semax; this modification is considered to alter its reaction characteristics with redox agents and copper ions, among other things, and may increase its stability even more. 

Selank Peptide: What is it? 

The Russian Academy of Sciences also developed another heptapeptide, Selank. This tetrapeptide, an analog of the naturally occurring tuftsin (threonine, lysine, proline, and arginine), has a Pro-Gly-Pro fragment at its C-terminus and was synthesized. 

Usually found in the Fc-domain of the heavy chain of immunoglobulin G (residues 289–292), tuttsin is an immunomodulatory peptide in the blood cells of specific animals. Hence, Selank may have immunomodulatory impacts alongside its anxiolytic and nootropic potential. 

Research indicates that the peptide may traverse the blood-brain barrier (BBB) and exert its impact by binding to certain receptors in the central nervous system. 

Semax and Selank: Mechanism of Action

When deciding whether peptide warrants more exploration for their particular requirements, researchers should take into account the processes underlying both Selank and Semax: 

Semax Peptide

Investigations purport that Semax may increase CNS concentrations of neurotrophic factors via interactions with these factors. In particular, it has been theorized to enhance the expression of NGF and Brain-Derived Neurotrophic Factor (BDNF). 

Scientific studies have indicated that when given with Semax, BDNF levels may rise by 1.4-fold, and trkB (tropomyosin receptor kinase B, also referred to as tropomyosin-related kinase B receptor) gene expression may increase by 22-fold. Some neurons in the brain have a receptor for BDNF called tropomyosin receptor kinase B. 

Potentially useful in studies related to mood disorders, including anxiety and depression, the peptide seems to influence the brain’s signaling of serotonin and dopamine. 

According to one research study, both peptides seem to influence enkephalin signaling. Upregulating enkephalins, which are the endogenous ligands for opioid receptors, may have positive impacts on mood and stress levels. 

Selank Peptide 

Studies have suggested that after being presented, Selank can potentially increase BDNF expression in the hippocampus region of rats’ brains. 

However, the peptide seems to affect opioid, serotonergic, and GABA signaling much more. These processes are probably foundational to Selank’s potential to alleviate anxiety and stress. 

Additional study is required to determine the exact processes by which the peptide interacts with dopamine and norepinephrine, although some have speculated this may be the case. 

Semax and Selank: Cognition

Both Semax and Selank have been hypothesized to provide nootropic impacts, as suggested by the experimental data that is currently available: 

Semax Peptide

A study examined how the peptide may have affected memory and attention in models of fatigue. Researchers theorized that those given Selank appeared to have had a much higher rate of right responses on a memory test (71% vs. 41%) after only one exposure and that this effect  may have lasted up to 24 hours. 

Additional research used resting-state functional magnetic resonance imaging (fMRI) to examine how Semax may have affected the brain’s neural network. The study examined 24 research models using three resting-state fMRI scans. There appeared to be a statistically significant increase in the volume of the medial prefrontal cortex subcomponent of the default mode network in the Semax group compared to the control group. 

Selank Peptide 

Research models with anxiety-phobic, hypochondriac, and somatoform disorders seemed to have strong nootropic impacts in an experimental study with Selank. By presenting the peptide with a traditionally accepted compound, its effectiveness was hypothesized to be greatly enhanced without the usual unwanted effects of benzodiazepines.

The same researchers also highlighted Selank’s possible nootropic properties in a separate study, suggesting that the compound may have produced anxiolytic impacts similar to the control compound.

Scientists interested in Semax or Selank peptides are encouraged to navigate the Biotech Peptides website for the highest-quality research compounds.