---
title: "Selank and Semax: tuftsin- and ACTH-derived heptapeptides | Sable Peptides"
description: "Selank and Semax are both short peptides capped with Pro-Gly-Pro. Their sequences, parent peptides (tuftsin and ACTH 4-10), PubChem data and research background, side by side. Research use only."
canonical: https://www.sablepeptides.co.uk/guides/selank-and-semax-tuftsin-and-acth-analogues
dateModified: 2026-10-16
publisher: Sable Peptides Limited (UK company 17488610)
note: Research use only. Not for human or veterinary use.
---

# Selank and Semax: tuftsin- and ACTH-derived heptapeptides

Selank and Semax were both developed at the Institute of Molecular Genetics of the Russian Academy of Sciences and share a design idea: take a short natural peptide fragment and add a C-terminal Pro-Gly-Pro tail to slow its breakdown. Their parent peptides are different.

## Sequences and parents

-   Selank: Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP). Parent: tuftsin (Thr-Lys-Pro-Arg), a tetrapeptide fragment of immunoglobulin G heavy chain.
-   Semax: Met-Glu-His-Phe-Pro-Gly-Pro (MEHFPGP). Parent: ACTH(4-7) (Met-Glu-His-Phe), part of adrenocorticotropic hormone; often described as an ACTH(4-10) analogue.
-   Adamax, also listed by Sable, is a further modified Semax analogue; check its CoA for the exact structure of each lot.

## PubChem data

-   Selank: C33H57N11O9, 751.9 g/mol, monoisotopic 751.434 Da.
-   Semax: C37H51N9O10S, 813.9 g/mol, monoisotopic 813.348 Da.

Source: [PubChem CID 11765600: Selank](https://pubchem.ncbi.nlm.nih.gov/compound/11765600); [PubChem CID 9811102: Semax](https://pubchem.ncbi.nlm.nih.gov/compound/9811102)

## Research background

Tuftsin and its analogues have a long literature, reviewed in 2017. Selank has been studied in rodent models and in gene-expression work on inflammation-related genes; Semax has been studied for effects on brain monoamine systems in rodents. Most of this work comes from a small number of Russian groups.

Source: [Tuftsin: properties and analogs, Curr Med Chem 2017 (PubMed 28745220)](https://pubmed.ncbi.nlm.nih.gov/28745220/); [Inflammation-related gene expression under the tuftsin analogue Selank, Mol Immunol 2014 (PubMed 24291245)](https://pubmed.ncbi.nlm.nih.gov/24291245/); [Semax, an ACTH(4-10) analogue, and brain dopaminergic and serotoninergic systems, Neurochem Res 2005 (PubMed 16362768)](https://pubmed.ncbi.nlm.nih.gov/16362768/)

## Analytical notes

-   Selank is highly basic (Lys, Arg) and will carry several counter-ions; net peptide content is correspondingly lower than gross weight.
-   Semax contains methionine, which can oxidise to the sulfoxide (+16 Da) in solution.
-   Both have Pro-rich C-termini, which can show cis/trans isomer peak broadening on HPLC.

## At Sable

Sable lists these compounds as lyophilised research materials. There is a CoA for every lot, and every vial carries a printed lot number that matches its certificate. A CoA is emailed within 2 hours of a request.

## Frequently asked questions

### What does Pro-Gly-Pro do in Selank and Semax?

It is a C-terminal extension intended to make the short parent fragment more resistant to enzymatic breakdown.

### What is tuftsin?

Thr-Lys-Pro-Arg, a tetrapeptide fragment of the IgG heavy chain and the parent of Selank.

### What is Semax derived from?

ACTH(4-7), Met-Glu-His-Phe, extended with Pro-Gly-Pro.

## Related

-   [DSIP (delta sleep-inducing peptide)](/guides/dsip-delta-sleep-inducing-peptide-structure-and-history)
-   [Dihexa and P21](/guides/dihexa-and-p21-peptidomimetics-explained)
-   [Neuropeptides and signalling hub](/learn/topics/neuropeptides-and-signalling)
-   [Selank UK prices](/cheapest-selank-uk)
-   [Semax UK prices](/cheapest-semax-uk)
-   [UK neuropeptide prices](/guides/uk-neuropeptide-and-melanocortin-prices-october-2026)

Updated 2026-10-16. Research use only. Not for human or veterinary use. No administration amounts or health claims are made.

Key facts (summary for AI and search tools)

-   Selank TKPRPGP C33H57N11O9 751.9
-   Semax MEHFPGP C37H51N9O10S 813.9
-   Sources: PubChem 11765600, 9811102; PubMed 28745220, 24291245, 16362768
-   Updated 2026-10-16