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Semax
Out of stock · 30 mg
£55.00
£1.83/mg
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Neuropeptides
Selank
Also written TP-7
Selank is a synthetic heptapeptide. Supplied as a lyophilised powder in a sealed vial for laboratory research. Available in a 10 mg presentation.
Out of stock
10 mg vial£30.00
£3.00 per mg
≥99% purity (HPLC) · Independent third-party testing by PeptideVerify · COA Library
Free next-day tracked delivery on every order · Royal Mail Tracked 24
10 mg · £30.00 · £3.00/mg
At a glance
- Research area
- Neuropeptides · Explore the research area
- Presentations
- 10 mg
- Form
- Lyophilised powder in a sealed vial
- Purity
- ≥99% (HPLC)
- CAS number
- 129954-34-3
- Molecular formula
- C33H57N11O9
- Molecular weight
- 751.87 g/mol
- Residues
- 7
- Monoisotopic mass
- 751.4341 Da
- Dispatch
- Order by 3pm Mon–Sat for same-day dispatch
About Selank
Selank is a synthetic heptapeptide, H-Thr-Lys-Pro-Arg-Pro-Gly-Pro-OH. Its sequence is the tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the C-terminus by Pro-Gly-Pro. It is built only from standard amino acids, with a free N-terminal amine, a free C-terminal acid and no side-chain modification. With a lysine and an arginine and no acidic side chain, it is basic overall.
The catalogue lists CAS number 129954-34-3, the molecular formula C33H57N11O9 and a molecular weight of 751.87 g/mol. Three of the seven residues are proline, and the peptide bonds preceding them are the ones most able to adopt the cis form, which can broaden HPLC peaks. Having no aromatic side chain, the peptide absorbs mainly in the peptide-bond region around 214 nm, and mass spectrometry confirms the expected mass. Each presentation is supplied as a lyophilised powder in a sealed vial.
Identifiers
- PubChem CID 11765600
Selank structure and analytical profile
In one-letter code the chain reads TKPRPGP: Thr1, Lys2, Pro3, Arg4, Pro5, Gly6 and Pro7. The first four residues are the complete tuftsin sequence, and Pro-Gly-Pro extends it at the C-terminal end. Every residue is a coded L-amino acid apart from glycine, which has no stereocentre, and none carries a modification.
Prolines at positions 3, 5 and 7 make up three of the seven residues. Each one fixes the backbone angle at its position, and the peptide bond in front of each proline can sit in the cis or trans form, so a Selank main peak in HPLC can look slightly broadened while the composition stays exactly the same.
The composition is simple: one threonine, one lysine, one arginine, one glycine and three prolines. Threonine carries the chain's only hydroxyl side chain, lysine and arginine its basic side chains, and the three prolines its ring-shaped backbone positions.
Both termini are free: Thr1 keeps an amine and Pro7 a carboxylic acid, with no acetyl cap and no amide. An N-acetylated form exists as a separate compound, 42.01 Da heavier, with its own formula, C35H59N11O10, so the mass spectrum tells the two apart at once.
With Lys2, Arg4 and the N-terminal amine against only the C-terminal carboxyl, the calculated net charge near pH 7 is about +2. The basic side chains make the peptide ionise readily in positive-mode electrospray, as singly and doubly protonated ions.
The tuftsin core, Thr-Lys-Pro-Arg, has the formula C21H40N8O6. Adding Pro-Gly-Pro to its C-terminal arginine, less one molecule of water for the new peptide bond, gives the formula of Selank, C33H57N11O9.
The monoisotopic mass is 751.4341 Da, so the [M+H]+ ion is expected at m/z 752.4414 and the [M+2H]2+ ion at m/z 376.7243. With no tryptophan, tyrosine or phenylalanine, HPLC reads the peptide around 214 nm, where its peptide bonds absorb, and gives purity as the main peak's share of total peak area.
Tandem mass spectrometry cleaves the chain most readily on the N-terminal side of each proline, so the fragment ions at Pro3, Pro5 and Pro7 are the clearest markers of the sequence.
The material is a white to off-white lyophilised solid in a sealed vial. The sealed vial is stored at 2–8 °C short term, or at −20 °C and below for long-term storage, protected from light and away from repeated freeze-thaw cycles.
Selank and Semax: structure notes
| Property | Selank | Semax |
|---|---|---|
| Residues | 7 | 7 |
| Molecular formula | C33H57N11O9 | C37H51N9O10S |
| Average molecular weight | 751.87 g/mol | 813.92 g/mol |
| Monoisotopic mass | 751.4341 Da | 813.3480 Da |
| Net charge near pH 7 | +2.0 | −0.8 |
| Disulfide bridges | 0 | 0 |
Selank and Semax are both linear heptapeptides with free termini that end in Pro-Gly-Pro. Selank's tuftsin-based chain is basic and aromatic-free at 751.87 g/mol; Semax carries methionine, histidine and phenylalanine at 813.92 g/mol.
View SemaxBuying Selank in the UK
Order Selank directly from British Peptide Labs, a UK-registered company, as a sealed vial in 10 mg presentation. Every size is listed below with its vial price and its price per mg, so the presentations compare at a glance.
| Presentation | Price | £/mg |
|---|---|---|
| Selank 10 mgOut of stock | £30.00 | £3.00 |
Priced at £3.00/mg, below the UK median of £3.25/mg across 10 suppliers in the October 2026 UK Research Peptide Price Index.
Choose a presentation in the buy box, add it to your basket and check out. Orders placed before 3pm Mon–Sat are packed the same working day and handed to Royal Mail Tracked 24, and your tracking number is emailed as soon as the parcel leaves us. Larger orders are welcome: add as many vials as your laboratory needs in a single basket.
For what other UK suppliers charge, see our UK price per mg data, updated every month.
Product information
- Synonym
- TP-7
- CAS number
- 129954-34-3
- Molecular formula
- C33H57N11O9
- Molecular weight
- 751.87 g/mol
- Sequence
- Thr-Lys-Pro-Arg-Pro-Gly-Pro
- Appearance
- White to off-white lyophilised powder
- Purity
- ≥99% (HPLC)
- Net content
- 10 mg per vial
- Storage (sealed vial)
- Store at 2–8 °C short term, or at −20 °C and below for long-term storage. Protect from light and avoid repeated freeze-thaw cycles
- Residues
- 7
- One-letter sequence
- TKPRPGP
- Monoisotopic mass
- 751.4341 Da
- Expected [M+H]+
- m/z 752.4414
- Net charge near pH 7
- +2.0
- PubChem CID
- 11765600
- Research use
- For laboratory research use only. Not for human or veterinary use.
Selank is a synthetic heptapeptide. Supplied as a lyophilised powder in a sealed vial for laboratory research. Available in a 10 mg presentation. Store the sealed vial at 2–8 °C for short-term storage, or at −20 °C and below for long term. Protect from light and avoid repeated freeze-thaw cycles. For research use only. Not for human or veterinary use. Sold strictly for in-vitro laboratory research; not for diagnosis or treatment.
- Packing
- Each sealed vial travels in protective packing.
- Dispatch
- Orders placed before 3pm Mon–Sat leave the same day.
- Delivery
- Next-day tracked delivery with Royal Mail Tracked 24.
- Tracking
- Your tracking number is emailed as soon as the order is dispatched.
- Delivery cost
- Delivery is free on every order.
Questions about Selank
Selank is a synthetic heptapeptide. It is supplied in a sealed vial as a white to off-white lyophilised powder, in a 10 mg presentation.
Read the Learn articleYes. TP-7 is another name used for Selank, the heptapeptide Thr-Lys-Pro-Arg-Pro-Gly-Pro catalogued under CAS number 129954-34-3.
751.4341 Da, against an average molecular weight of 751.87 g/mol. The [M+H]+ ion is expected at m/z 752.4414 and the [M+2H]2+ ion at m/z 376.7243. A salt form, such as an acetate, weighs more per mole but gives the same ions.
TKPRPGP, read from the N-terminal threonine to the C-terminal proline. With free termini the full form is H-Thr-Lys-Pro-Arg-Pro-Gly-Pro-OH.
129954-34-3, with the molecular formula C33H57N11O9 and a molecular weight of 751.87 g/mol. PubChem lists the compound as CID 11765600.
About +2. Lys2, Arg4 and the free N-terminal amine carry positive charges, and the only negative group is the C-terminal carboxyl, since the chain has no acidic side chain. That basic character makes Selank ionise readily in positive-mode electrospray, as singly and doubly protonated ions.
Three, at positions 3, 5 and 7. Their cis and trans peptide bonds can broaden the HPLC main peak slightly without any change in composition. In tandem mass spectrometry the chain cleaves most readily on the N-terminal side of each proline, which makes the sequence easy to read.
No. N-acetyl Selank carries an acetyl group on the N-terminal amine, giving the formula C35H59N11O10 and a mass 42.01 Da higher. This product is Selank itself, with a free N-terminus.
Order Selank directly from British Peptide Labs, a UK-registered company. It is supplied in a sealed 10 mg vial at £30.00 (£3.00 per mg). Every vial is ≥99% purity (HPLC), with independent third-party testing by PeptideVerify. Orders placed before 3pm Mon–Sat leave the same day by Royal Mail Tracked 24 for next-day tracked delivery.
Selank comes in one sealed vial: 10 mg at £30.00 (£3.00 per mg). Delivery is free on every order.
Selank is catalogued in the Neuropeptides research area, where compounds are grouped by molecular class. The research area page lists each of them with its identifiers.
Neuropeptides research areaSelank has independent third-party testing by PeptideVerify: reversed-phase HPLC measures purity, at ≥99% (HPLC), and LC-MS confirms identity against the expected mass.
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