For research purposes only. This comparison describes the chemical identity and research context of Semax and Selank. It is not medical advice, does not rank the compounds for any purpose, and does not describe any effect, dose, or use in humans or animals.
Semax vs Selank at a glance
| Attribute | Semax | Selank |
| Class | ACTH(4-10) analogue (heptapeptide) | Tuftsin analogue (heptapeptide) |
| Length | 7 aa | 7 aa |
| Approx. molecular weight | ~813.9 g/mol | ~751.9 g/mol |
| Receptor / target (research) | Neuropeptide research | Neuropeptide research |
| CAS number | 80714-61-0 | 129954-34-3 |
What is Semax?
Semax is a synthetic heptapeptide (seven amino acids) with the sequence Met-Glu-His-Phe-Pro-Gly-Pro (MEHFPGP), structurally related to a fragment of ACTH(4-10). It is supplied as a lyophilised powder for laboratory research.
Read more in our Semax research guide, or view the Semax product page.
What is Selank?
Selank is a synthetic heptapeptide (seven amino acids) with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP), structurally based on the peptide tuftsin. It is supplied as a lyophilised powder for laboratory research.
Read more in our Selank research guide, or view the Selank product page.
Key differences
Both are synthetic heptapeptides from the same lineage of Russian neuropeptide research, but they derive from different parent sequences. Semax is based on the ACTH(4-10) fragment (sequence MEHFPGP); Selank is based on the immunomodulatory peptide tuftsin (sequence TKPRPGP). Both add a Pro-Gly-Pro tail relative to their parent sequence for improved stability.
How researchers distinguish Semax and Selank
In neuropeptide research the two are often studied in parallel as representatives of different parent peptides (an ACTH fragment versus tuftsin). The selection between them is an experimental-design choice tied to the pathway under investigation.
Frequently asked questions
No. Both are synthetic heptapeptides, but Semax is based on the ACTH(4-10) fragment (MEHFPGP) and Selank is based on tuftsin (TKPRPGP).
Their parent sequences: Semax derives from ACTH(4-10), Selank from tuftsin. They have different amino-acid sequences and molecular weights.
Both come from the same field of Russian neuropeptide research and are frequently discussed together as related synthetic heptapeptides.
Both are available from PurePeptides at greater than 99% purity as lyophilised powders, with same-day dispatch before 3PM and tracked UK & EU delivery. They are sold strictly for laboratory research use only.
Research-grade Semax & Selank
Greater than 99% purity, lyophilised powder, same-day dispatch before 3PM with tracked UK & EU delivery. Research use only.
Buy Semax → Buy Selank →Disclaimer: All products supplied by PurePeptides are strictly for laboratory research use only. They are not for human or animal consumption and are not medical products. This comparison is informational and summarises publicly available research; it is not medical, clinical, or dosing advice.