Semax vs Selank: Mechanism, Specs & Reported Ranges Compared
Side-by-side comparison of Semax and Selank — receptor mechanism, half-life, vial sizes, reconstitution and reported study arms.
By PX1 Research Team · August 4, 2026
Semax vs Selank at a glance
| Semax | Selank | |
|---|---|---|
| Class | ACTH(4-10) analog nootropic peptide | tuftsin analog heptapeptide |
| Reported half-life | not well characterized | not well characterized |
| Vial sizes | 30 mg vial / 50 mg nasal | 10 mg vial / 40 mg nasal |
| Typical reconstitution | 30 mg + 3 mL = 10 mg/mL | 10 mg + 2 mL = 5 mg/mL |
| Research focus | BDNF and cognitive-model research | anxiolytic-pathway and GABA research |
Mechanistic difference
Semax derives from ACTH(4-10) and is studied in BDNF and cognition models; Selank is a tuftsin analog studied in anxiolytic and GABAergic contexts.
Reported study ranges side by side
Semax
| Study arm | Reported amount | Cadence |
|---|---|---|
| Standard arm | 300–600 mcg | daily intranasal |
Selank
| Study arm | Reported amount | Cadence |
|---|---|---|
| Standard arm | 250–500 mcg | daily intranasal |
Practical handling differences
Both arrive lyophilized and shelf-stable. Semax is typically prepared at 30 mg + 3 mL = 10 mg/mL; Selank at 10 mg + 2 mL = 5 mg/mL. Where half-lives differ, the literature's dosing cadence differs accordingly — longer-acting molecules are described weekly, shorter-acting ones daily or split.
Which one appears in which research context
Semax shows up primarily in BDNF and cognitive-model research. Selank is used in anxiolytic-pathway and GABA research. They are not interchangeable substitutes; the receptor profile, not the marketing category, determines where each is used.
Documentation and sourcing
Both are supplied at ≥99% HPLC purity with lot-level COAs at /coa. Product pages: Semax · Selank.
How PX1 documents every lot
Every PX1 lot ships with HPLC purity, LC-MS identity, residual solvent, moisture (Karl Fischer), sterility and endotoxin data. Lot documentation is published at /purity-reports, /endotoxin-reports and /coa. Synthesis, purification, lyophilization and vial fill happen in U.S. facilities — see /manufacturing-process.
Research use only. PX1 Research supplies compounds for laboratory and in-vitro research. Nothing here is medical advice, a dosing recommendation, or an offer for human or veterinary use. Figures cited are reported from published laboratory literature.