Short answers to the questions researchers ask most about storing, mixing and handling Semax, the Met-Glu-His-Phe-Pro-Gly-Pro heptapeptide. Semax is a seven-residue analogue of the ACTH(4-7) fragment with a Pro-Gly-Pro tail, and most of its handling rules follow from two features of that sequence: an N-terminal methionine that oxidises in solution, and a highly polar structure that dissolves easily in water. Each answer links to the page in this reference that covers it in more depth, and the storage windows match how long Semax lasts.
How should lyophilised Semax be stored?
Keep the sealed vial in the fridge at 2 to 8 °C for everyday storage, or in the freezer for long-term storage, in its box and away from light. Let a cold vial reach room temperature before opening it so condensation does not form on the cake. The dry powder is Semax’s most stable form, and the full windows are on the Semax storage page.
How long does Semax last after mixing?
Mixed with bacteriostatic water and kept at 2 to 8 °C, upright and dark, Semax lasts 8 to 12 weeks under Vistara Labs’ handling guidance, with quality slowly fading from around week 6 to 8. Write the mixing date on the vial so you know where you are in that window. No published stability study of Semax in bacteriostatic water was found, so this is general peptide guidance applied to a short, enzyme-resistant sequence.
What do you mix Semax with?
Bacteriostatic water, which is sterile water with 0.9% benzyl alcohol for multi-access vials. Semax is a short, hydrophilic peptide, so it needs no acetic acid, co-solvent or saline. Run the water slowly down the inside wall of the vial and swirl gently rather than shaking. Volumes and concentrations are on the Semax reconstitution page.
How much bacteriostatic water goes in a 10 mg Semax vial?
There is no single correct volume. With 2 mL a 10 mg vial gives 5 mg/mL, and with 1 mL it gives 10 mg/mL, the same strength as the registered 1% Russian nasal drops. Adding more water does not change how much Semax is in the vial; it only lowers the concentration, so write the concentration you chose on the vial.
Why is my mixed Semax cloudy?
Semax dissolves to a clear, colourless solution, so cloudiness usually comes from technique: water jetted onto the cake, shaking, or a cold vial opened before it warmed up. Give a fresh vial a few minutes of gentle swirling at room temperature; a solution that stays cloudy, or turns hazy weeks later, is discarded.
What makes Semax degrade?
Its N-terminal methionine oxidises in solution, and oxygen, light, warmth and trace metals speed that up. Semax has no asparagine, glutamine, aspartate or cysteine, so the other common peptide degradation routes do not apply, and its Pro-Gly-Pro tail makes it unusually resistant to peptidases (Shevchenko et al., Bioorganicheskaya Khimiya, 2013).
Can you freeze mixed Semax?
It is not recommended. Freezing concentrates solutes and dissolved oxygen into the unfrozen fraction and stresses the stopper seal, and repeated freeze-thaw makes it worse. Keep a mixed vial in the main body of the fridge rather than the door, where the temperature swings each time it opens. The sealed lyophilised vial, by contrast, can go in the freezer for long-term storage.
Does Semax need to be refrigerated during shipping?
No. Lyophilised Semax travels without an ice pack because a dry solid has almost no water for degradation chemistry to happen in. On arrival, put vials in the fridge or freezer and the ready-mixed nasal spray in the fridge. A vial with a broken seal or a wet-looking residue is kept aside unopened.
How do you store the Semax nasal spray?
The Semax Nasal Spray is ready-mixed in a metered pump that delivers 0.175 mL per press, so it is kept like a mixed vial: in the fridge, upright, capped and out of light, and never frozen. More care notes are in how to store a peptide nasal spray.
Does mixed Semax change colour when it degrades?
Not reliably. Methionine sulfoxide, the main oxidation product, is colourless, so a clear solution past 12 weeks is still past its window. A yellow tint, flakes or strands mean the solution is discarded whatever its date.
Where to go next
The chemistry behind these answers is on the Semax stability page and the Semax solubility page, bench practice is on the handling page, and first steps with a new order are on the on-arrival page. The research summary and molecular data are on the Semax overview, and the lyophilised vial is Semax 10 mg.
All products supplied by Vistara Labs are intended for laboratory research use only. They are not drugs, are not approved for human or veterinary use, and are not intended to diagnose, treat, cure or prevent any condition. Nothing on this page constitutes medical advice or guidance for use in humans.
