Selank is the synthetic heptapeptide Thr-Lys-Pro-Arg-Pro-Gly-Pro. See Peptide Foundry’s CAS/formula anchors and the purity panels to demand on a lot COA. Research use only.
- CAS Number
- 129954-34-3
- Molecular Formula
- C33H57N11O9 C33H57N11O9
- Molar Mass
- 751.9 g/mol
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-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 tuftsin-related listing, and not a synonym for the related heptapeptide Semax.
If you found “selank,” “selank peptide supplier,” “selank third party tested,” “high purity selank,” or “selank vs semax” in a listing, the useful questions are which sequence and CAS the seller claims, whether the certificate matches those registry fields, and how the lot is documented. Aliases vary; registry fields and certificates do not.
This page covers Peptide Foundry’s published identity anchors, the purity panels a research buyer should demand, a worked ILS Laboratories lot, and a short Semax sibling note — then soft-handoffs to the gated Selank research product page. Research use only.
Key points
- Selank = synthetic heptapeptide Thr-Lys-Pro-Arg-Pro-Gly-Pro (tuftsin tetrapeptide with C-terminal Pro-Gly-Pro); supplied as lyophilized research material.
- Peptide Foundry catalog anchors (live PDP): CAS 129954-34-3, formula C33H57N11O9, molar mass 751.9 g/mol, PubChem 11765600 — match certificate fields to these claims.
- 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: Semax is a different heptapeptide (ACTH(4-10) fragment with C-terminal Pro-Gly-Pro; CAS 80714-61-0) — co-discussed in research catalogues, not a synonym for Selank.
- Research use only — not for human or veterinary use.
What is Selank?
Selank is a seven-residue synthetic peptide: threonine–lysine–proline–arginine–proline–glycine–proline (Thr-Lys-Pro-Arg-Pro-Gly-Pro). Residue count is seven (heptapeptide). Structurally it corresponds to the tuftsin tetrapeptide (Thr-Lys-Pro-Arg) 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 tuftsin 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-SELANK 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 Selank, Thr-Lys-Pro-Arg-Pro-Gly-Pro shorthand, and informal “tuftsin 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 Selank. 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: Thr-Lys-Pro-Arg-Pro-Gly-Pro (threonyl-lysyl-prolyl-arginyl-prolyl-glycyl-proline). Residue count: 7 (heptapeptide). Parent motif: tuftsin (Thr-Lys-Pro-Arg) with C-terminal Pro-Gly-Pro. SKU PF-SELANK; size option on the live listing at publish time: 10 mg lyophilized.
CAS, formula, and molar mass
| Field | Peptide Foundry catalog (live /product/selank/) |
|---|---|
| CAS | 129954-34-3 |
| Formula | C33H57N11O9 |
| Molar mass | 751.9 g/mol |
| PubChem CID | 11765600 |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro |
| Residues | 7 |
| SKU | PF-SELANK |
| Form | Lyophilized |
| Size (live option) | 10 mg |
Market pages sometimes round mass differently, omit PubChem, or recycle CAS strings across unrelated listings. 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.
What a Selank 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 Selank,” 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 FO657
As published on the current Peptide Foundry Selank listing at the time of writing:
| Field | Value |
|---|---|
| Lot | FO657 |
| Size | 10 mg |
| Laboratory | ILS Laboratories (ISO/IEC 17025 narrative on live copy) |
| Received | 08/26/2026 |
| Purity | 99.46% (HPLC @ 214 nm) |
| Net peptide content | 10.2 mg |
| Identity | HPLC-RTM — Pass |
| Fentanyl screen | Not Detected |
| Heavy metals | Pass |
| Sterility | No Growth |
| Endotoxin | 0.13 EU/mL |
| Access code | 38LSHMAY |
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 FO657:
- Match the lot number on the vial to the lot on the certificate.
- Confirm CAS, formula, sequence, and labeled mass against the certificate and the product label.
- Verify the access code on the issuing laboratory’s own portal (ILS for FO657: access code 38LSHMAY) — 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: Semax (sibling, not synonym)
Research catalogues often co-list Semax beside Selank. Shared C-terminal Pro-Gly-Pro design notes in published descriptions do not make the two materials interchangeable. Semax is a different synthetic heptapeptide built on an ACTH(4-10) fragment motif rather than a tuftsin parent.
| Field | Selank (primary) | Semax (sibling) |
|---|---|---|
| Parent motif | Tuftsin (Thr-Lys-Pro-Arg) | ACTH(4-10) |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Met-Glu-His-Phe-Pro-Gly-Pro |
| Shared design note | C-terminal Pro-Gly-Pro | C-terminal Pro-Gly-Pro |
| CAS | 129954-34-3 | 80714-61-0 |
| Formula | C33H57N11O9 | C37H51N9O10S |
| Molar mass | 751.9 g/mol | 813.9 g/mol |
| PF SKU / size | PF-SELANK / 10 mg | PF-SEMAX / 10 mg |
Dedicated sibling literacy: Semax research identity. Soft related listing: Semax research product page. Match each vial to its own sequence, CAS, and lot certificate. Shared design notes are chemistry literacy — not a protocol for combining materials.
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.
| Literature class (examples) | Acceptable framing on this page | Not used as product framing |
|---|---|---|
| GABAergic signaling | Examined in preclinical publications exploring GABAergic signaling endpoints in rodent or cultured systems | Consumer product claims framed as personal GABA effects |
| Monoamine metabolism | Investigated in rodent assays of monoamine metabolism | Mood-product or monoamine “fix” claims |
| Tuftsin-related immunomodulatory pathways | Studied in models examining tuftsin-related immunomodulatory pathways | Immune-therapy or patient-immunity product claims |
| Neurotrophic-factor expression | Examined in preclinical work on neurotrophic-factor expression endpoints | Consumer “brain boost” or cognitive-enhancement product claims |
| Tuftsin / Institute origin | Naming and structural history for tuftsin + Pro-Gly-Pro | Approved-medicine framing as Peptide Foundry product use |
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 Selank. General lyophilized-material diluent literacy (without compound-specific schedules) lives at Lyophilized peptide reconstitution.
Common questions
What is Selank’s sequence and CAS?
Sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro; CAS 129954-34-3; formula C33H57N11O9; molar mass 751.9 g/mol; PubChem CID 11765600. Peptide Foundry catalogs the material as SKU PF-SELANK (10 mg lyophilized option at publish time). Prefer registry fields over listing nicknames.
Is Selank the same as Semax?
No. Semax is a different heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) built on an ACTH(4-10) 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. Sibling page: Semax research identity.
What makes a Selank 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 FO657 figures above — ILS Laboratories, HPLC 99.46% @ 214 nm, HPLC-RTM pass, net 10.2 mg, access code 38LSHMAY — are an example of that pattern on Peptide Foundry’s live listing. Workflow detail: How to read a research-peptide COA.
Should Selank and Semax be used together?
This page does not recommend combining research materials. Selank and Semax are chemically distinct heptapeptides with different CAS, sequences, formulas, and lot documentation. Shared Pro-Gly-Pro design notes are structural literacy only. Match each vial to its own certificate if both appear in a catalogue.
Is this a nootropic, a cognitive enhancer, or for human use?
No. Peptide Foundry supplies Selank strictly for laboratory and research use by qualified researchers. Mentions of GABAergic signaling, monoamine metabolism, tuftsin-related immunomodulatory pathways, or neurotrophic-factor expression 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 finished goods, personal-use schedules, or administration protocols. Selank 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 Selank research product page. Related library reading: Semax research identity, How to read a research-peptide COA, USA research-peptide vendor criteria, Lyophilized peptide reconstitution, Epithalon research identity, and GHK-Cu research identity.
Research use only. Nothing on this page describes or implies use in humans or animals. Pathway-class mentions of GABAergic signaling, monoamine metabolism, tuftsin-related immunomodulatory pathways, or neurotrophic-factor expression refer only to preclinical and in-vitro literature contexts and are not product outcomes.
