Quick answer
Source Semax only with an HPLC trace, mass-spec identity near 814 Da and a COA whose lot number matches the vial.
- Compound: Met-Glu-His-Phe-Pro-Gly-Pro, ACTH-derived core plus stabilizing Pro-Gly-Pro tail
- Verify: HPLC with method, mass spectrometry, batch COA, lot traceability
- Red flags: usage instructions, no lot match, prices far below market
- V8 listing: Semax, 15 mg lyophilized; see the CoA library
- Concentration: mg ÷ mL; see the calculator
For laboratory research use only; not for human consumption.
Why Semax sourcing is a documentation question
Semax sits in an unusual spot in the research-peptide landscape: it is derived from a fragment of ACTH, extended with a stabilizing Pro-Gly-Pro tail, and studied mostly for neurotrophic and cognition-related readouts rather than the metabolic or tissue-repair endpoints that dominate this field. That narrower, more specialized literature base makes supplier evaluation slightly different from a compound like BPC-157 or semaglutide: there is less redundant third-party data circulating, so the burden on the supplier's own documentation is higher.
The sequence is Met-Glu-His-Phe-Pro-Gly-Pro, a heptapeptide of about 814 Da (formula C37H51N9O10S). The first four residues correspond to positions 4–7 of ACTH, and the Pro-Gly-Pro tail is the stabilizing addition. Compound background is in the Semax research overview and what is Semax.
| Property | Semax | ACTH(4-10) fragment |
|---|---|---|
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Met-Glu-His-Phe-Arg-Trp-Gly |
| Approximate mass | About 814 Da | About 962 Da |
| Length | 7 residues | 7 residues |
| Distinguishing feature | Pro-Gly-Pro tail | Native residues 8–10 |
| Relative stability in models | Stabilized | Short-lived |
What to check before ordering
- HPLC purity with the method disclosed. A bare percentage on a label does not tell you the column, gradient, or detection wavelength used to generate it. See understanding HPLC purity.
- Batch-specific Certificate of Analysis, tied to the exact lot shipped, not a generic template reused across production runs. See how to read a COA.
- Mass spectrometry identity confirmation. Verifying that the molecular weight matches the heptapeptide sequence, not just that something eluted at a plausible retention time. This matters more for a short peptide like Semax, where a truncated or deletion-sequence byproduct can be close enough in mass to slip past a cursory check. See HPLC vs. mass spectrometry.
- Lot traceability. The lot number printed on the vial should match the lot number on the COA. If they do not line up, the documentation is not actually linked to what shipped.
- No human-use or usage language. A supplier presenting Semax with intranasal instructions or health-outcome claims is marketing outside appropriate research-use boundaries, and that should be read as a documentation red flag, not just a marketing choice.
- Storage guidance and research-use-only labeling consistent across the product page, packaging, and any accompanying literature.
What the analytical data should look like
Knowing what a good result looks like makes a certificate easier to evaluate. At about 814 Da, Semax gives a simple mass spectrum, usually dominated by the singly charged [M+H]+ ion near m/z 815. Common deviations are predictable.
| Observation | Likely meaning | Mass relative to parent |
|---|---|---|
| Signal at 16 Da higher | Methionine sulfoxide (oxidation), a storage indicator | +16 Da |
| Signal about 97 Da lower | Proline deletion in the tail | About −97 Da |
| Signal near 962 Da | ACTH(4-10) fragment, not Semax | About +148 Da |
| Small early-eluting pre-peak on HPLC | Oxidized species, more polar than parent | Same chain, +16 Da |
| Broad or split main peak | Co-eluting species or poor method | Check method conditions |
The N-terminal methionine is the residue to watch: it oxidizes on exposure to air, and the size of the sulfoxide pre-peak tells you something about how a lot has been stored. Fuller analytical detail is in Semax purity testing.
Why the price floor matters
Producing research-grade Semax involves solid-phase synthesis, reversed-phase HPLC purification, mass spec confirmation, and lyophilization (what is lyophilization). Each step has a real, non-trivial cost even for a short seven-residue chain. Pricing that sits well below the market range for a peptide at this purity tier is a signal worth investigating before ordering, not a bargain to take at face value. The most common shortcuts at the low end of the market are skipping mass spec confirmation entirely or accepting a lower-purity batch to avoid a second purification pass.
A fairer comparison is cost per milligram of peptide actually present, which depends on net content. Two vials with the same label mass and the same HPLC purity can contain different amounts of peptide if one retains more counter-ion and water. Asking whether a supplier reports net content is a quick test of how carefully the material is characterized.
Evaluating a supplier's research content
Because Semax's literature base skews toward non-English-language sources, with much of the foundational pharmacology coming from Russian research institutions, the quality of a supplier's own educational material is a reasonable proxy for how carefully they have engaged with the compound versus repackaged someone else's summary. Look for content that distinguishes the ACTH-derived core from the stabilizing Pro-Gly-Pro extension, acknowledges that Semax's initiating molecular target is still not fully mapped, and keeps research-use framing consistent throughout rather than treating it as boilerplate bolted onto the bottom of the page. For the proposed mechanism and design rationale, see V8's Semax research overview. Related variants are compared in N-acetyl Semax amidate vs. Semax, and the sibling regulatory peptide in Selank vs. Semax.
Receiving, storing and preparing material
The V8 product page lists Semax as a lyophilized powder in a sealed glass research vial, stored at 2–8 °C with −20 °C for long-term storage, protected from heat, moisture and light. On arrival, confirm the lot number, keep the vial cold and dark, and let it warm to room temperature before opening to avoid condensation. For lab concentrations, divide labeled mass by diluent volume: a 15 mg vial in 3 mL is a nominal 5 mg/mL stock, about 6.1 mM at 814 g/mol. The peptide calculator does this arithmetic for any vial size, and net peptide content, where known, should be applied as a correction. General storage practice is in storing research peptides.
| Labeled mass | Diluent volume | Nominal concentration | Approx. molarity (MW about 814) |
|---|---|---|---|
| 15 mg | 1.5 mL | 10 mg/mL | About 12.3 mM |
| 15 mg | 3 mL | 5 mg/mL | About 6.1 mM |
| 15 mg | 7.5 mL | 2 mg/mL | About 2.5 mM |
Common sourcing mistakes
Four errors recur when labs buy short neuropeptides. The first is accepting a purity statement without a trace: without the chromatogram there is no way to judge whether a pre-peak from oxidation was integrated into the main peak. The second is treating a certificate for one lot as covering another; Semax oxidizes with storage time, so the age of the test matters as well as its existence. The third is assuming a label mass equals peptide mass, which ignores counter-ions and water. The fourth is skipping a retained-sample check: keeping a small aliquot from the lot received allows re-testing by HPLC if an assay result later looks unexpected.
None of these requires specialized equipment to avoid. They require asking for the documents, matching the lot numbers, writing down the date, and keeping a reference sample. The same habits apply to the sibling compound Selank and to nearly every peptide a lab buys.
Where to buy documented Semax
V8 Peptides supplies Semax as a 15 mg lyophilized powder with a listed HPLC purity of at least 98% and the sequence Met-Glu-His-Phe-Pro-Gly-Pro stated on the page. A batch-specific Certificate of Analysis is published on the site and covers purity, identity and lot details; the product page shows whether a particular lot's certificate is complete or still in progress, so check that before ordering. The product page is Semax research vial, and lot documents are collected in the CoA library. For a general framework on evaluating any research peptide supplier, see the supplier checklist; researchers comparing regulatory peptides may also consult Selank.
Where to Buy High-Purity Semax for Research FAQ
What mass should a Semax certificate show?
About 814 Da for the complete heptapeptide. A signal 16 Da higher indicates methionine oxidation.
How is Semax distinguished from ACTH(4-10)?
The two differ in their last three residues and by roughly 148 Da in mass, so mass spectrometry separates them clearly.
Why is mass spectrometry important for a short peptide?
Deletion or truncation products can look similar on HPLC. A mass spectrum shows directly whether the full seven residues are present.
What does a small peak just before the main HPLC peak mean?
Commonly the methionine sulfoxide form, which is more polar and elutes slightly earlier. Its size indicates how the lot has been stored.
Does a matching lot number matter?
Yes. A certificate only describes the batch it was run on. If the lot number on the vial and the document differ, the document does not apply to that vial.
Why check how a supplier describes Semax's mechanism?
Its initiating molecular target is not fully mapped. Content that states this plainly is a better sign of care than content that overstates certainty.
How should lab concentrations be calculated?
Divide labeled peptide mass by diluent volume to get mg/mL, then adjust for net peptide content if known. The calculator does this.
Where is the V8 product page?
At Semax, with lot documents in the CoA library.
Research Use Only. For laboratory research use only; not for human consumption. This article is research education, not usage guidance.