Neuropeptides
Selank vs Semax: Research Comparison
Selank and Semax are synthetic seven-amino-acid peptides developed by Russian researchers, and both end in Pro-Gly-Pro. Selank is built from tuftsin, a short peptide involved in immune signalling. Semax is built from a short fragment of the hormone ACTH.
Side-by-side comparison
| Attribute | Selank | Semax |
|---|---|---|
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Met-Glu-His-Phe-Pro-Gly-Pro |
| Parent peptide | Tuftsin (Thr-Lys-Pro-Arg) | ACTH fragment (Met-Glu-His-Phe) |
| Findings by model | Rats: changed BDNF levels in the hippocampus. Mice: changed inflammation-related genes. Human blood samples: slowed enkephalin breakdown | Rats: raised BDNF and its receptor TrkB in the hippocampus |
| Human data | One small study comparing it with an existing drug, not placebo-controlled | Small Russian clinical studies, not placebo-controlled |
Detailed analysis
Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) adds Pro-Gly-Pro to tuftsin. Its mechanism is not fully worked out. In human blood samples it slowed the breakdown of enkephalins, the body's own opioid-like peptides (Zozulya et al., 2001). In rats it changed BDNF levels in the hippocampus (Inozemtseva et al., 2008), and in mice it changed the activity of inflammation-related genes (Kolomin et al., 2011).
Semax (Met-Glu-His-Phe-Pro-Gly-Pro) adds Pro-Gly-Pro to a fragment of ACTH and is often described as an analogue of ACTH(4-10). In rats it raised levels of BDNF and its receptor TrkB in the hippocampus (Dolotov et al., 2006). It is used as a medicine in Russia.
For both, most research comes from a small number of Russian groups and is published largely in Russian journals. The human studies are small and not placebo-controlled, and independent placebo-controlled trials have not been published.
Key differences
- ·Selank is built from tuftsin; Semax is built from a fragment of ACTH.
- ·Selank slowed enkephalin breakdown in human blood samples; Semax raised BDNF and TrkB in rats.
- ·Neither has independent placebo-controlled trials.
Research summary
Both peptides come from Russian research programmes, and most findings are from rats, mice and blood samples (Dolotov et al., 2006; Zozulya et al., 2001). Human studies are small and not placebo-controlled. Long-term safety is unknown. Supplied for laboratory research use only.