Research

Selank Explained: the Tuftsin Analogue, Its Mass and How to Verify a Batch

3 min read · Research blog · 12 Nov 2026 · By CellMind Research Team

Selank is a synthetic peptide of seven amino acids with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP). It is an analog of the natural peptide tuftsin and has a molecular mass of 751.89 Da. This guide explains its structure, what the literature covers and how to verify a batch.

Key facts

Type: Synthetic heptapeptide (seven amino acids); analog of tuftsin
Sequence: Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP)
Molecular formula: C33H57N11O9
Molecular mass: 751.89 Da
CAS number: 129954-34-3
Supplied as: lyophilized powder in a sealed vial

What is Selank

Selank was developed at the Institute of Molecular Genetics of the Russian Academy of Sciences. Its first four amino acids are those of tuftsin (Thr-Lys-Pro-Arg), a fragment of an antibody chain. Three more residues, Pro-Gly-Pro, were added at the end to make the peptide more stable against enzymes.

What the scientific literature covers

Published work was carried out mainly in cell cultures and animal models. The main topics are:

Expression of genes linked to GABA signaling in rat brain tissue
Behavioral models in rodents
Enzymes that break down enkephalins in serum
Expression of immune signaling genes in mice

These are laboratory findings. CellMind supplies Selank for research purposes only, not for human use.

How identity and purity are verified

Selank contains three prolines and two basic residues (lysine and arginine), so it is polar and elutes fairly early on reversed-phase HPLC. HPLC separates the target peptide from shortened sequences. Mass spectrometry confirms 751.89 Da, which tells it apart from Semax (about 813.9 Da), a related peptide that ends in the same Pro-Gly-Pro tail. Both results must appear on the certificate of analysis (CoA) for the specific batch. Our CoA guide explains how to read one.

Checklist before buying Selank

A CoA for the specific batch
HPLC purity stated as a number, above 99%
Mass of 751.89 Da confirmed on the report
A clearly stated amount per vial (10 mg)
A batch number on the vial that matches the report

Common questions about Selank

How is Selank different from Semax?

Both end in Pro-Gly-Pro, but the first part differs. Selank starts with the tuftsin sequence Thr-Lys-Pro-Arg (751.89 Da in total). Semax starts with Met-Glu-His-Phe, a fragment of the hormone ACTH (about 813.9 Da in total).

How is Selank different from tuftsin?

Tuftsin is the four-amino-acid peptide Thr-Lys-Pro-Arg (about 500.6 Da). Selank is tuftsin with Pro-Gly-Pro added at the end.

What mass should a Selank report show?

751.89 Da for the free peptide. Salt forms weigh more, so the report should state which form was measured.

Storage and handling

Keep lyophilized vials in a cool, dark place. After reconstitution the solution should be refrigerated and used within the planned study period. Avoid repeated temperature changes: they are the most common cause of degradation that nobody notices until results stop matching.