Home Research library Semax vs Selank
Comparison
Semax vs Selank
Semax and Selank are separate research compounds. This page sets what our catalogue and the laboratory certificates state about each one side by side: identifiers, formula, molecular weight, chain length, form and storage. It describes the materials, not what they do, and carries no use guidance.
Specification, side by side
| Semax | Selank | |
|---|---|---|
| Also known as | Met-Glu-His-Phe-Pro-Gly-Pro | None listed |
| Catalogue shelf | Research peptides | Research peptides |
| CAS number | 80714-61-0 | 129954-34-3 |
| Molecular formula | C37H51N9O10S | C33H57N11O9 |
| Molecular weight | 813.9 g/mol | 751.9 g/mol |
| Chain length | 7 residues | 7 residues |
| Sequence | MEHFPGP | TKPRPGP |
| Form as supplied | Lyophilized powder | Lyophilized powder |
| Storage | -20 °C, desiccated | -20 °C, desiccated |
| Sizes stocked | 10 mg | 10 mg |
| Current certificates | 10 mg: 99.82%, lot SEMX10-0803 | 10 mg: 99.83%, lot SEL10-0803 |
| PubChem record | CID 9811102 | CID 11765600 |
Figures are the ones printed on each product page. Purity appears only where a current laboratory certificate supports it, and links to that certificate.
What differs
- Semax and Selank are each 7 residues long; they differ in which residues those are.
- Molecular weight: Semax is 813.9 g/mol and Selank is 751.9 g/mol. Semax is the largest of the two.
- Each has its own CAS registry number (Semax: 80714-61-0 and Selank: 129954-34-3), which is how a chemical supplier tells them apart on paper.
- Their molecular formulas differ: C37H51N9O10S for Semax and C33H57N11O9 for Selank.
What each one is
Semax
A heptapeptide built on the ACTH(4-7) fragment with a Pro-Gly-Pro tail that slows enzymatic breakdown. Used to study BDNF and NGF expression, TrkB signalling and monoamine turnover in neuronal culture and rodent models. One of the most studied of the Russian-origin regulatory peptides. See Semax.
Selank
A tuftsin analogue with the same Pro-Gly-Pro stabilising tail as semax. Used as a probe for GABA-A receptor expression, monoamine metabolism and the enkephalin-degrading enzymes, mostly in rodent anxiety and learning paradigms. See Selank.
Common questions
Are Semax and Selank the same compound?
No. They are separate compounds with separate CAS registry numbers: 80714-61-0 for Semax and 129954-34-3 for Selank. They are sold as separate items and certified separately.
Which is the larger molecule, Semax or Selank?
Semax, at 813.9 g/mol. Selank is 751.9 g/mol.
Is there a certificate of analysis for Semax and Selank?
Semax has 1 current certificate and Selank has 1 current certificate in the testing library, each linked to the laboratory's own file.
Does this page say what Semax and Selank are used for?
No. It compares the materials as chemicals: identifiers, formula, weight, chain length, form and storage. Everything here is sold for laboratory research use only, and the site publishes no use guidance.
Further reading
- Semax and Selank: two heptapeptides and their US statusSemax (MEHFPGP) is four residues of ACTH plus a Pro-Gly-Pro tail; Selank (TKPRPGP) is the tetrapeptide tuftsin plus the same tail. Where each came from, what the spelling variants mean, and their status as of September 2026.
Other comparisons
For laboratory research use only. Not a drug, not a supplement, not for human or veterinary use.