Semax and Selank are often mentioned together. Both are short synthetic peptides developed at the Institute of Molecular Genetics of the Russian Academy of Sciences, and both end in the same Pro-Gly-Pro tail. They come from different parent peptides, though, and researchers study them for different reasons.
Side-by-side
| Semax | Selank | |
|---|---|---|
| Parent peptide | ACTH(4-10) fragment | Tuftsin (Thr-Lys-Pro-Arg) |
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Thr-Lys-Pro-Arg-Pro-Gly-Pro |
| Length | 7 amino acids | 7 amino acids |
| CAS number | 80714-61-0 | 129954-34-3 |
| Molecular formula | C37H51N9O10S | C33H57N11O9 |
| Molecular weight | 813.9 g/mol | 751.9 g/mol |
Semax
Semax is built from a fragment of adrenocorticotropic hormone (ACTH 4-10), with Pro-Gly-Pro added to slow its breakdown. In rodent studies it has been examined mainly for its effects on brain-derived neurotrophic factor (BDNF) expression.
Selank
Selank is an analog of tuftsin, a four-amino-acid fragment of immunoglobulin G, again extended with Pro-Gly-Pro. Rodent research has looked at its effects on behavior in anxiety models and on GABAergic and monoamine signaling.
Regulatory status
Neither peptide is FDA approved. Both are sold here for laboratory research use only.
Formats and prices
| Product | Format | Price |
|---|---|---|
| Semax Spray | Liquid in a spray bottle | $110.00 |
| Selank Spray | Liquid in a spray bottle | $110.00 |
| Selank / Semax Spray | Both peptides in one spray bottle | $165.00 |
| Selank 10mg | Lyophilized powder, 10mg per vial | $55.00 |
Prices as of November 2026.
Testing
Our manufacturer tests it twice during production, and we use an independent third-party lab for purity testing. A COA is available on request.
FAQ
What is the difference between Semax and Selank?
Semax is a synthetic analog of the ACTH(4-10) fragment, while Selank is a synthetic analog of tuftsin. Both are seven amino acids long and end in Pro-Gly-Pro.
Where were Semax and Selank developed?
Both were developed at the Institute of Molecular Genetics of the Russian Academy of Sciences.
What are the CAS numbers for Semax and Selank?
Semax is CAS 80714-61-0 (C37H51N9O10S) and Selank is CAS 129954-34-3 (C33H57N11O9).
Are Semax and Selank FDA approved?
No. Neither is FDA approved, and both are sold for laboratory research use only.
Are Semax and Selank tested?
Our manufacturer tests it twice during production, and we use an independent third-party lab for purity testing. A COA is available on request.
All products mentioned are sold for laboratory research use only and are not for human consumption.