Semax: what it is, how it is supplied, and how to choose a research supplier

Semax is a synthetic peptide of seven amino acids: methionine, glutamic acid, histidine, phenylalanine, proline, glycine, proline: written Met-Glu-His-Phe-Pro-Gly-Pro or MEHFPGP.

The first four residues are the fragment 4–7 of adrenocorticotropic hormone (the piece known as ACTH(4-10) once the natural continuation is dropped); the C-terminal Pro-Gly-Pro was added to make the chain more resistant to enzymatic cleavage.

Its molecular weight is about 813 Da.

It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences, the same laboratory that designed Selank.

The two share the Pro-Gly-Pro tail and a similar size, which is why they are often listed together and occasionally mislabelled.

Semax is a white to off-white lyophilized powder with no color and no smell.

The methionine in position 1 is the one residue to watch: it can oxidize to methionine sulfoxide over time, which is why the sealed vial is kept cold and dark and why the HPLC purity on the COA matters: the oxidized form shows up as a separate peak.

In the catalog, Semax is sold as a research reagent: a sealed, labeled vial of lyophilized powder. Research use only. Not for human or veterinary use.

Further reading: epithalon data sheet, sermorelin data sheet and Glutathione peptide.

Same laboratory, same sizes, same white powder: but two different molecules. A listing that presents them as interchangeable has not read the report.

Each is a separate compound, in its own vial, with its own label naming it.

Research Semax comes as a lyophilized (freeze-dried) powder in a glass vial closed with a rubber septum and an aluminum crimp cap. The label states the compound, the net quantity in milligrams and the words "research use only".

The catalog offers two sizes: 5 mg and 10 mg: and the price per milligram is lower on the 10 mg vial.

The live table at the top of this page is read directly from the catalog, so the prices shown there are the prices in force today. See Semax in the catalog for availability.

What "5 mg" means on the label

The number is the net mass of Semax powder in the vial, as filled, and it is the quantity printed on the label.

Five milligrams of lyophilized peptide is a thin white film, not a visible heap; an almost empty-looking vial is the normal appearance of this size.

Acetate or trifluoroacetate

Synthetic peptides are supplied as a salt. Most research Semax is the acetate; some manufacturers leave the trifluoroacetate (TFA) counter-ion from purification.

The COA should state which. Neither changes the sequence, but residual TFA is a purity question, and it is one of the differences between a manufacturer's lot and a re-bottled one.

For Semax, the COA answers two questions at once: is it the right molecule, and has the methionine stayed intact? A usable certificate carries:

• The laboratory's name and a verifiable identifier. Independent labs (Janoshik is the reference for this market) give each test a number that anyone can look up on the lab's site.
• The lot number: with the task number and verification key the laboratory confirms.
• HPLC purity as a measured percentage. Some labs add a chromatogram; a second peak just before the main one is where the oxidized (sulfoxide) form appears; a clean single peak is what a fresh lot looks like.
• Identity by name. Some labs add mass spectrometry showing an observed mass of about 813 Da; a mass 16 Da higher is the oxidized form; a mass of about 751 Da means the vial holds Selank.
• The date of the test. A certificate older than a few months describes a lot that has probably sold through.
• A photograph of the tested vial wearing the supplier's own label. A manufacturer's certificate showing a bare vial says nothing about what this supplier bottled.

What some chromatograms and mass spectra look like is in how to read a peptide COA; what a purity figure does and does not mean is in HPLC purity: what "> 99 %" means.

Semax is stable as a lyophilized powder when it is kept cold, dark and dry, and the methionine makes the "dark" and "sealed" parts matter more than for most peptides. The catalog's storage line for the sealed vial:

• Temperature: −20 °C for long-term storage, in the sealed vial, away from light and moisture.
• Light: keep the vial in its box or in an opaque container.
• Moisture and air: keep the vial sealed. Let a cold vial reach room temperature before removing it from its bag, so no condensation forms on the glass.
• Shelf life: 24 months from the fill date for a sealed vial stored as above.

Shipping at ambient temperature for a few days does not degrade the sealed powder; that is why research peptides ship without cold packs. The general rules, size by size, are in lyophilized peptides: storage and shelf life.

"Semax for sale" returns marketplaces, resellers and a handful of research suppliers. To sort them, ask six questions of the product page: not of the marketing.

1. What does the supplier's lab documentation cover? Before buying from any supplier, check which compounds and sizes its reports name, and that each one can be looked up on the laboratory's site.
2. Is the vial sealed, with a printed label naming the compound, its net mass in mg and "research use only"?
3. Does the report name Semax as the compound found, with a high HPLC purity? An old or badly stored lot shows the oxidized form as a second peak.
4. Does the supplier ship from EU stock, tracked, in a few days?
5. Does the page describe the product only (composition, purity, storage) with "research use only" stated plainly? A supplier that publishes usage content is a supplier that is easy to shut down; that risk transfers to any order in transit.
6. Is the price read per mg, size by size? It is the fairest way to compare two listings of the same compound.

The wider checklist (payment, packaging, what to do if a parcel is stopped) is in where to buy research peptides in Europe. The seven checks that can be run on a product page before paying are in how to check a peptide supplier.

Further reading: MOTS-c buying guide and CJC-1295 / Ipamorelin blend.

The price of research Semax depends on the size of the vial and where it ships from.

The catalog table at the top of this page shows the current price per vial and per milligram for each size; the 10 mg vial has the lower cost per milligram.

What the price includes at OXpeptides: a sealed, labeled vial and the lyophilized compound inside, named with its net quantity in mg on the label. Ships from the EU · tracked: €9.90, free from €120.

See Semax in the catalog →