Semax Research Peptide: Identity, CAS & Third-Party Testing Expectations

Semax is the synthetic heptapeptide Met-Glu-His-Phe-Pro-Gly-Pro (ACTH(4-10) + Pro-Gly-Pro). Peptide Foundry identity anchors, third-party testing expectations for research-grade Semax, and soft notes on related Selank. Research use only.

Last reviewed 11 September 2026 · For research use only

CAS Number

80714-61-0

Molecular Formula

C₃₇H₅₁N₉O₁₀S C37H51N9O10S

Molar Mass

813.9 g/mol

Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is a discrete research material with its own CAS, formula, molar mass, and lot documentation — not a catalogue nickname for every ACTH-fragment listing, not an amidate by default, and not a synonym for the related heptapeptide Selank.

If you found “semax,” “semax peptide supplier,” “semax third party tested,” “high purity semax,” or “semax amidate” in a listing, the useful questions are which sequence and CAS the seller claims, whether the certificate describes free-acid or C-terminal amide form, and how the lot is documented. Aliases vary; registry fields and certificates do not.

This page covers Peptide Foundry’s published identity anchors, sulfur-in-formula literacy, the purity panels a research buyer should demand, a worked ILS Laboratories lot, and a short Selank sibling note — then soft-handoffs to the gated Semax research product page. Research use only.

Key points

• Semax = synthetic heptapeptide Met-Glu-His-Phe-Pro-Gly-Pro (ACTH(4-10) fragment with C-terminal Pro-Gly-Pro); supplied as lyophilized research material.
• Peptide Foundry catalog anchors (live PDP): CAS 80714-61-0, formula C₃₇H₅₁N₉O₁₀S, molar mass 813.9 g/mol, PubChem 9811102 — match certificate fields to these claims; the formula must include methionine sulfur (S).
• Demand a lot-matched COA: HPLC purity with method/wavelength when stated, identity method, named laboratory, and preferably independent portal verify; “third-party tested” or “high purity” without lot + named lab is unfinished.
• Related sibling: Selank is a different heptapeptide (tuftsin + Pro-Gly-Pro; CAS 129954-34-3) — co-discussed in research catalogues, not a synonym for Semax.
• Research use only — not for human or veterinary use.

What is Semax?

Semax is a seven-residue synthetic peptide: methionine–glutamic acid–histidine–phenylalanine–proline–glycine–proline (Met-Glu-His-Phe-Pro-Gly-Pro). Residue count is seven (heptapeptide). Structurally it corresponds to an ACTH(4-10) fragment with a C-terminal Pro-Gly-Pro extension described in published assay literature. The research material on this page is that defined synthetic sequence — not a crude tissue extract and not a brand stack.

A short historical note anchors naming only. Work associated with the Institute of Molecular Genetics (Russian Academy of Sciences) literature described defined synthetic sequences related to ACTH-fragment research, including the Pro-Gly-Pro extension as a structural design choice discussed in preclinical assay papers (often framed there as stability characteristics in those experimental systems). That is origin and naming history — not a product claim, not a catalogue mechanism story, and not registry proof.

Physical form on research listings is lyophilized solid. Peptide Foundry’s current lot documents describe lyophilized powder under SKU PF-SEMAX at a 10 mg size option. Appearance is a handling observation — not a purity proof and not a substitute for HPLC or identity data on a certificate.

Market aliases include Semax, MEHFPGP shorthand, and informal “ACTH(4-10) analog” language. Aliases help search and inventory. They are not identity proof until you have CAS, formula, molar mass, sequence, and a lot-matched certificate.

Chemical identity anchors

Peptide Foundry publishes a fixed identity set for single-vial Semax. The values below match the live catalog chemistry table at the time of writing. Confirm against the current product page if a lot or chemistry block rotates after publish.

Sequence and composition

Sequence: Met-Glu-His-Phe-Pro-Gly-Pro (methionyl-glutamyl-histidyl-phenylalanyl-prolyl-glycyl-proline). Residue count: 7 (heptapeptide). The N-terminal methionine contributes a sulfur atom that must appear in the molecular formula. SKU PF-SEMAX; size option on the live listing at publish time: 10 mg lyophilized.

CAS, formula, and molar mass

Market pages sometimes round mass to 813.93 Da, omit PubChem, or publish a formula that drops the methionine sulfur. The practical rule is: match the vendor’s stated CAS + formula + molar mass + sequence to the lot COA, then prefer orthogonal identity (MS / HPLC-RTM) over the nickname alone.

Sulfur / formula check (buyer literacy)

Semax begins with methionine. Methionine contains sulfur. Peptide Foundry’s published free-acid formula is therefore C₃₇H₅₁N₉O₁₀S — the terminal S is not optional. A listing that claims Semax sequence while omitting sulfur from the formula is a documentation mismatch worth resolving before purchase. Historical catalog corrections in this category exist for exactly that reason: teach buyers to check the sulfur atom against the Met residue rather than trusting a nickname string alone.

Free acid vs amidate (sourcing check)

Some vendors list C-terminal amide or “semax amidate” forms under a Semax-like marketing name. An amidated C-terminus changes formula and mass relative to the free-acid heptapeptide even when sellers reuse the same label or, in some cases, cite a similar CAS string.

Peptide Foundry publishes the free-acid formula C₃₇H₅₁N₉O₁₀S and molar mass 813.9 g/mol. At publish time Peptide Foundry does not list a separate Semax amidate SKU. Queries such as “semax amidate third party tested” are answered here as literacy: read terminus form, formula, and mass on the certificate, then decide whether the vial matches the vendor’s published anchors.

Practical rule: match terminus form + formula + molar mass + sequence on the lot COA to the vendor’s chemistry table. Do not assume every “Semax” label is the free-acid form Peptide Foundry publishes, and do not invent a universal second CAS “winner” for amidate listings. That is a chemical-identity check for purchasing and documentation — keep it there.

What a Semax COA should show

A certificate of analysis is stronger when it is lot-specific, names the laboratory, states methods, and can be checked outside the supplier’s own site. For the full verification workflow — batch match, named lab, HPLC versus identity, biosafety panels, portal codes — see How to read a research-peptide COA.

Minimum research COA fields

• A lot / batch ID that matches the vial character for character
• Test or report date(s) and a named laboratory
• HPLC purity with method (and wavelength when stated — for example 214 nm)
• An identity method (MS and/or HPLC-RTM)
• Product name / sequence consistent with the label and the vendor’s published anchors

“Third-party tested,” “high purity Semax,” or “99%+” without a named lab and a lot number is an unfinished claim. A pretty PDF that cannot be tied to the vial in hand is documentation theater. That distinction answers the supplier-intent queries researchers actually type — purity and verification language without inventing a consumer category.

Stronger panels (when claimed)

When a full QC panel is present — the pattern on current ILS-tested Peptide Foundry lots — read these as separate analytical results:

• Mass-spectrometry or HPLC-RTM identity confirmation
• Net peptide content versus labeled mass when reported
• Heavy metals by ICP-MS against stated limits
• Sterility / no growth
• Endotoxin (for example USP <85> / LAL)
• Illicit-substance screen (for example fentanyl — not detected)

These describe composition and contamination panels for research documentation. They are not a safety-for-human-use claim, and they do not replace identity or purity.

Worked example — lot FO889

As published on the current Peptide Foundry Semax listing at the time of writing:

Cite those figures as Peptide Foundry–published transparency for this lot — not a universal industry floor. Re-verify against the live product panel if the lot rotates after publish.

Three steps that travel with any lot, not just FO889:

1. Match the lot number on the vial to the lot on the certificate.
2. Confirm CAS, formula, sequence, and labeled mass against the certificate and the product label — including free-acid versus amidate language if present, and confirming sulfur in the formula.
3. Verify the access code on the issuing laboratory’s own portal (ILS for FO889: access code 2PPRRVLN) — not only by opening a PDF hosted by the supplier.

A PDF on a supplier site is a document the supplier controls. A record you can pull from the testing laboratory is not. Portable vendor criteria beyond a single SKU: USA research-peptide vendor criteria.

Related research heptapeptide: Selank (sibling, not synonym)

Research catalogues often co-list Selank beside Semax. Shared C-terminal Pro-Gly-Pro design notes in published descriptions do not make the two materials interchangeable. Selank is a different synthetic heptapeptide built on a tuftsin (Thr-Lys-Pro-Arg) parent motif rather than an ACTH(4-10) fragment.

One-line lot note (confirm against the live Selank panel if rotated): Peptide Foundry’s published Selank documentation at write time includes ILS Laboratories lot FO657 at 99.46% HPLC @ 214 nm (access 38LSHMAY). That is sibling transparency — not a second worked-example focus on this page. Soft related reading: Selank research identity; gated listing: Selank research product page. Match each vial to its own sequence, CAS, and lot certificate.

Pathway-class literacy (preclinical / in vitro only)

Mechanism language is useful here only as classification of experimental systems in published literature. It does not establish catalogue-product outcomes in people, and it does not convert a citation into a certificate. Keep this section shorter than identity and COA literacy.

Cerebrovascular or human clinical literature that appears in wider SERPs sits outside the scope of this RUO identity page and is not summarized as product use. Keep pathway class attached to the source paper and the experimental system. Identity remains an analytical question answered by CAS, formula, sequence, and the lot COA.

Storage and lab handling (lyophilized)

Standard laboratory practice for lyophilized synthetic peptides applies:

• Storage. Sealed vials at −20°C, protected from light and moisture. Lyophilized material is substantially more stable than solution.
• Temperature excursions. Brief ambient exposure in transit is normal for lyophilized material. Return vials to −20°C on arrival.
• Freeze–thaw. Minimize repeated freeze–thaw.
• Traceability. Keep the lot number with the material — lot number ties a vial back to its certificate.

Assay-specific handling follows your institution’s SOPs. This page does not publish personal reconstitution schedules or solution-use protocols for Semax. For general lyophilized diluent literacy (BAC vs AA; no compound-specific schedules), see Lyophilized peptide reconstitution.

Common questions

What is Semax’s sequence and CAS?

Sequence Met-Glu-His-Phe-Pro-Gly-Pro; CAS 80714-61-0; formula C₃₇H₅₁N₉O₁₀S; molar mass 813.9 g/mol; PubChem CID 9811102. Peptide Foundry catalogs the material as SKU PF-SEMAX (10 mg lyophilized option at publish time). Prefer registry fields over listing nicknames.

Is Semax the same as Selank?

No. Selank is a different heptapeptide (Thr-Lys-Pro-Arg-Pro-Gly-Pro) built on a tuftsin parent motif. Both share a C-terminal Pro-Gly-Pro design note in published descriptions; they do not share CAS, formula, mass, or sequence. Match each vial to its own certificate.

What makes a Semax COA usable — and what does “third-party tested” require?

Lot match to the vial, a named laboratory, HPLC purity with method/wavelength when stated, an identity method (MS and/or HPLC-RTM), and preferably an independent portal verify path. Stronger documentation adds net peptide content, heavy metals, sterility, endotoxin, and illicit screens when claimed. Worked FO889 figures above — ILS Laboratories, HPLC 99.62% @ 214 nm, HPLC-RTM pass, net 10.25 mg, access code 2PPRRVLN — are an example of that pattern on Peptide Foundry’s live listing. Workflow detail: How to read a research-peptide COA.

What about “semax amidate”?

Other vendors may offer C-terminal amide forms under a Semax-like name. Those are different terminus presentations. Peptide Foundry publishes free-acid C₃₇H₅₁N₉O₁₀S / 813.9 g/mol and does not list a separate Semax amidate SKU at publish time. Match formula and mass on the COA before treating any “Semax” label as interchangeable.

Is this a nootropic, a cognitive enhancer, a stroke treatment, a nasal product, or for human use?

No. Peptide Foundry supplies Semax strictly for laboratory and research use by qualified researchers. Mentions of BDNF/NGF gene expression, melanocortin receptor binding, or monoaminergic signaling in published preclinical and in-vitro literature are pathway-class context only — not product benefits and not human therapy. This page does not describe consumer brain products, cerebrovascular treatment or prevention, nasal administration protocols, or personal-use schedules. Semax here is not a drug, supplement, consumer finished good, or veterinary product, and not for use in people or animals.

For the current lot certificate and product specifications, see the gated Semax research product page. Related library reading: How to read a research-peptide COA, USA research-peptide vendor criteria, Selank research identity, Epithalon research identity, and General lyophilized diluent literacy.

Research use only. Nothing on this page describes or implies use in humans or animals. Pathway-class mentions of BDNF/NGF gene expression, melanocortin receptor binding, or monoaminergic signaling refer only to preclinical and in-vitro literature contexts and are not product outcomes.